Replace CSRF cookie with CrossOriginProtection (#36183)

Removes the CSRF cookie in favor of
[`CrossOriginProtection`](https://pkg.go.dev/net/http#CrossOriginProtection)
which relies purely on HTTP headers.

Fixes: https://github.com/go-gitea/gitea/issues/11188
Fixes: https://github.com/go-gitea/gitea/issues/30333
Helps: https://github.com/go-gitea/gitea/issues/35107

TODOs:

- [x] Fix tests
- [ ] Ideally add tests to validates the protection

---------

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

templates/repo/settings/public_access.tmpl

@@ -12,7 +12,6 @@
 		{{$paEveryoneRead := "everyone-read"}}
 		{{$paEveryoneWrite := "everyone-write"}}
 		<form class="ui form" method="post">
-			{{.CsrfTokenHtml}}
 			<table class="ui table unstackable tw-my-2">
 				<thead>
 					<tr>