feat!: remove legacy REST (#9594)

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## Description

ref: #7517 

  * [x] Remove the x/{module}/client/rest folder
  * [x] Remove all glue code between simapp/modules and the REST server

<!-- Add a description of the changes that this PR introduces and the files that
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---

### 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
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] 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`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification - see #9615
- [x] reviewed "Files changed" and left comments if necessary
- [x] 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...

- [x] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [x] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [x] reviewed API design and naming
- [ ] reviewed documentation is accurate - see #9615
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

x/auth/client/cli/query.go

@@ -10,7 +10,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	"github.com/cosmos/cosmos-sdk/types/rest"
+	"github.com/cosmos/cosmos-sdk/types/query"
 	"github.com/cosmos/cosmos-sdk/version"
 	authtx "github.com/cosmos/cosmos-sdk/x/auth/tx"
 	"github.com/cosmos/cosmos-sdk/x/auth/types"
@@ -199,8 +199,8 @@ $ %s query txs --%s 'message.sender=cosmos1...&message.action=withdraw_delegator
 	}
 
 	flags.AddQueryFlagsToCmd(cmd)
-	cmd.Flags().Int(flags.FlagPage, rest.DefaultPage, "Query a specific page of paginated results")
-	cmd.Flags().Int(flags.FlagLimit, rest.DefaultLimit, "Query number of transactions results per page returned")
+	cmd.Flags().Int(flags.FlagPage, query.DefaultPage, "Query a specific page of paginated results")
+	cmd.Flags().Int(flags.FlagLimit, query.DefaultLimit, "Query number of transactions results per page returned")
 	cmd.Flags().String(flagEvents, "", fmt.Sprintf("list of transaction events in the form of %s", eventFormat))
 	cmd.MarkFlagRequired(flagEvents)
 

x/auth/client/cli/tx_multisign.go

@@ -20,10 +20,16 @@ import (
 	signingtypes "github.com/cosmos/cosmos-sdk/types/tx/signing"
 	"github.com/cosmos/cosmos-sdk/version"
 	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
-	"github.com/cosmos/cosmos-sdk/x/auth/client/rest"
+	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 
+// BroadcastReq defines a tx broadcasting request.
+type BroadcastReq struct {
+	Tx   legacytx.StdTx `json:"tx" yaml:"tx"`
+	Mode string         `json:"mode" yaml:"mode"`
+}
+
 // GetSignCommand returns the sign command
 func GetMultiSignCommand() *cobra.Command {
 	cmd := &cobra.Command{
@@ -155,7 +161,7 @@ func makeMultiSignCmd() func(cmd *cobra.Command, args []string) (err error) {
 				return err
 			}
 
-			req := rest.BroadcastReq{
+			req := BroadcastReq{
 				Tx:   stdTx,
 				Mode: "block|sync|async",
 			}
@@ -338,7 +344,7 @@ func makeBatchMultisignCmd() func(cmd *cobra.Command, args []string) error {
 					return err
 				}
 
-				req := rest.BroadcastReq{
+				req := BroadcastReq{
 					Tx:   stdTx,
 					Mode: "block|sync|async",
 				}

x/auth/client/cli/tx_sign.go

@@ -10,7 +10,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	"github.com/cosmos/cosmos-sdk/client/tx"
 	authclient "github.com/cosmos/cosmos-sdk/x/auth/client"
-	"github.com/cosmos/cosmos-sdk/x/auth/client/rest"
 )
 
 const (
@@ -263,7 +262,7 @@ func makeSignCmd() func(cmd *cobra.Command, args []string) error {
 			if err != nil {
 				return err
 			}
-			req := rest.BroadcastReq{
+			req := BroadcastReq{
 				Tx:   stdTx,
 				Mode: "block|sync|async",
 			}