crypto: add keyring supported algorithms (#439)

* add keyring supported algorithms

* lint

* minor updates

* use eth_secp256k1 as the default signing algo

* add flag

* derivation func

* refactor

* rename keys amino registration

* fix keys

* address comments from review

cmd/ethermintd/genaccounts.go

@@ -22,6 +22,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/genutil"
 
 	"github.com/cosmos/ethermint/codec"
+	"github.com/cosmos/ethermint/crypto"
 	ethermint "github.com/cosmos/ethermint/types"
 
 	ethcrypto "github.com/ethereum/go-ethereum/crypto"
@@ -61,6 +62,7 @@ contain valid denominations. Accounts may optionally be supplied with vesting pa
 					viper.GetString(flags.FlagKeyringBackend),
 					viper.GetString(flagClientHome),
 					inBuf,
+					crypto.EthSecp256k1Options()...,
 				)
 				if err != nil {
 					return err