Add Deprecation headers for legacy rest endpoints (#7686)

* add deprecation headers for legacy rest endpoints

* add deprecation headers for missing tx routes

* rm handler-level deprecation headers

* switch to middleware Route.Use method for setting deprecation Headers

* set deprecation headers using subrouter

* cleanup gofmt

* goimports

* Update client/rest/rest.go

* update deprecation headers to be set on each module individually

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

types/module/module.go

@@ -31,9 +31,8 @@ package module
 import (
 	"encoding/json"
 
-	"github.com/grpc-ecosystem/grpc-gateway/runtime"
-
 	"github.com/gorilla/mux"
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
 	"github.com/spf13/cobra"
 	abci "github.com/tendermint/tendermint/abci/types"