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>

modules/structs/form.go

@@ -5,8 +5,7 @@ package structs
 
 import (
 	"gitea.dev/modules/translation/i18n"
-
-	"gitea.com/go-chi/binding" //nolint:depguard // avoid cycle import
+	"gitea.dev/modules/web/binding"
 )
 
 // ValidateContext is a special context for form validation middleware