[FEATURE] legacy amino support for authz module

[yun-yeo]

Problem definition
Columbus-4 has msgauth module, which is authz module in cosmos-sdk. cosmos-sdk fixed their implementation to support amino encoding for authz messages here.

Now we can add custom codec to authz messages to support old style tx signing.

func RegisterLegacyAminoCodec(cdc *codec.LegacyAmino) {
	cdc.RegisterInterface((*authz.Authorization)(nil), nil)

	cdc.RegisterConcrete(authz.MsgGrant{}, "msgauth/MsgGrantAuthorization", nil)
	cdc.RegisterConcrete(authz.MsgRevoke{}, "msgauth/MsgRevokeAuthorization", nil)
	cdc.RegisterConcrete(authz.MsgExec{}, "msgauth/MsgExecAuthorized", nil)
	cdc.RegisterConcrete(banktypes.SendAuthorization{}, "msgauth/SendAuthorization", nil)
	cdc.RegisterConcrete(authz.GenericAuthorization{}, "msgauth/GenericAuthorization", nil)
}

Feature specification
Add custom codec to support msgauth message amino signing.

Additional context
v0.5.x

[yun-yeo]

track cosmos/cosmos-sdk#9501