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/admin/notice.tmpl

@@ -34,7 +34,6 @@
 							<th></th>
 							<th colspan="5">
 								<form class="tw-float-right" method="post" action="{{AppSubUrl}}/-/admin/notices/empty">
-									{{.CsrfTokenHtml}}
 									<button type="submit" class="ui red small button">{{ctx.Locale.Tr "admin.notices.delete_all"}}</button>
 								</form>
 								<div class="ui floating upward dropdown small button">