refactor: Rename x/{mod}/legacy to x/{mod}/migrations (#9628)

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## Description

Closes: #8700 

<!-- Add a description of the changes that this PR introduces and the files that
are the most critical to review. -->

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [x] added `!` to the type prefix if API or client breaking change
- [x] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [x] provided a link to the relevant issue or specification
- [x] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [x] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [x] added a changelog entry to `CHANGELOG.md`
- [x] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [x] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

x/auth/ante/basic.go

@@ -7,7 +7,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 

x/auth/ante/setup.go

@@ -5,7 +5,7 @@ import (
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
 var (

x/auth/ante/sigverify.go

@@ -14,7 +14,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )

x/auth/ante/sigverify_test.go

@@ -16,7 +16,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/ante"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 

x/auth/client/rest/broadcast.go

@@ -10,7 +10,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client/tx"
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	"github.com/cosmos/cosmos-sdk/types/rest"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
 // BroadcastReq defines a tx broadcasting request.

x/auth/client/rest/decode.go

@@ -10,7 +10,7 @@ import (
 	clienttx "github.com/cosmos/cosmos-sdk/client/tx"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/rest"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 

x/auth/client/rest/encode.go

@@ -10,7 +10,7 @@ import (
 	clientrest "github.com/cosmos/cosmos-sdk/client/rest"
 	"github.com/cosmos/cosmos-sdk/client/tx"
 	"github.com/cosmos/cosmos-sdk/types/rest"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
 // EncodeResp defines a tx encoding response.

x/auth/client/rest/rest_test.go

@@ -28,7 +28,7 @@ import (
 	authcli "github.com/cosmos/cosmos-sdk/x/auth/client/cli"
 	authrest "github.com/cosmos/cosmos-sdk/x/auth/client/rest"
 	authtest "github.com/cosmos/cosmos-sdk/x/auth/client/testutil"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	bankcli "github.com/cosmos/cosmos-sdk/x/bank/client/testutil"
 	"github.com/cosmos/cosmos-sdk/x/bank/types"
 )

x/auth/client/tx.go

@@ -18,7 +18,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
 // GasEstimateResponse defines a response definition for tx gas estimation.

x/auth/client/tx_test.go

@@ -16,7 +16,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 )
 

x/auth/keeper/migrations.go

@@ -3,7 +3,7 @@ package keeper
 import (
 	"github.com/gogo/protobuf/grpc"
 
-	v043 "github.com/cosmos/cosmos-sdk/x/auth/legacy/v043"
+	v043 "github.com/cosmos/cosmos-sdk/x/auth/migrations/v043"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"

x/auth/migrations/legacytx/config_test.go

@@ -9,7 +9,7 @@ import (
 	cryptoAmino "github.com/cosmos/cosmos-sdk/crypto/codec"
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/testutil"
 )
 

x/auth/migrations/legacytx/stdsig_test.go

@@ -8,7 +8,7 @@ import (
 	yaml "gopkg.in/yaml.v2"
 
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
 func TestStdSignatureMarshalYAML(t *testing.T) {

x/auth/migrations/v038/types.go

@@ -20,7 +20,7 @@ import (
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/bech32/legacybech32"
-	v034auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v034"
+	v034auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v034"
 )
 
 const (

x/auth/migrations/v039/types.go

@@ -15,8 +15,8 @@ import (
 	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	v034auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v034"
-	v038auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v038"
+	v034auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v034"
+	v038auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v038"
 )
 
 const (

x/auth/migrations/v040/migrate.go

@@ -3,7 +3,7 @@ package v040
 import (
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	v039auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v039"
+	v039auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v039"
 	v040auth "github.com/cosmos/cosmos-sdk/x/auth/types"
 	v040vesting "github.com/cosmos/cosmos-sdk/x/auth/vesting/types"
 )

x/auth/migrations/v040/migrate_test.go

@@ -10,10 +10,10 @@ import (
 	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
 	"github.com/cosmos/cosmos-sdk/simapp"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	v034 "github.com/cosmos/cosmos-sdk/x/auth/legacy/v034"
-	v038auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v038"
-	v039auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v039"
-	v040auth "github.com/cosmos/cosmos-sdk/x/auth/legacy/v040"
+	v034 "github.com/cosmos/cosmos-sdk/x/auth/migrations/v034"
+	v038auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v038"
+	v039auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v039"
+	v040auth "github.com/cosmos/cosmos-sdk/x/auth/migrations/v040"
 )
 
 func TestMigrate(t *testing.T) {

x/auth/signing/handler_map_test.go

@@ -8,7 +8,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/crypto/keys/secp256k1"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 )

x/auth/signing/verify_test.go

@@ -14,7 +14,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth/ante"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
 	"github.com/cosmos/cosmos-sdk/x/bank/testutil"

x/auth/tx/legacy_amino_json.go

@@ -6,7 +6,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 

x/auth/tx/legacy_amino_json_test.go

@@ -9,7 +9,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 

x/auth/types/codec.go

@@ -4,7 +4,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec"
 	"github.com/cosmos/cosmos-sdk/codec/types"
 	cryptocodec "github.com/cosmos/cosmos-sdk/crypto/codec"
-	"github.com/cosmos/cosmos-sdk/x/auth/legacy/legacytx"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
 // RegisterLegacyAminoCodec registers the account interfaces and concrete types on the