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/projects/new.tmpl

@@ -9,7 +9,6 @@
 </h2>
 {{template "base/alert" .}}
 <form class="ui form" action="{{.Link}}" method="post">
-	{{.CsrfTokenHtml}}
 	<div>
 		<input type="hidden" id="redirect" name="redirect" value="{{.redirect}}">
 		<div class="field {{if .Err_Title}}error{{end}}">