Let web and API routes have different auth methods group (#19168)

* remove the global methods but create dynamiclly

* Fix lint

* Fix windows lint

* Fix windows lint

* some improvements

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/auth.go

@@ -0,0 +1,12 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//go:build !windows
+// +build !windows
+
+package web
+
+import auth_service "code.gitea.io/gitea/services/auth"
+
+func specialAdd(group *auth_service.Group) {}