refactor: move go-chi/binding into Gitea (#39528)

The `gitea.com/go-chi/binding` package only exists for Gitea, so it
moves into `modules/web/binding` to fix its bugs directly. Split out of
https://github.com/go-gitea/gitea/pull/39504.

- GET and HEAD always bind the query
- JSON `null` slice elements and nested `TrimSpace` fields bind
correctly
- Integer fields reject out-of-range values instead of wrapping
- An empty JSON body binds nothing and an unknown binding rule is an
error

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

services/forms/org.go

@@ -57,5 +57,5 @@ type CreateTeamForm struct {
 	Permission       string
 	RepoAccess       string
 	CanCreateOrgRepo bool
-	Visibility       string `binding:"OmitEmpty;In(public,limited,private)"`
+	Visibility       string `binding:"In(public,limited,private)"`
 }