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/lfs.tmpl

@@ -43,7 +43,6 @@
 						{{ctx.Locale.Tr "repo.settings.lfs_delete_warning"}}
 					</p>
 					<form class="ui form" action="{{$.Link}}/delete/{{.Oid}}" method="post">
-						{{$.CsrfTokenHtml}}
 						{{template "base/modal_actions_confirm"}}
 					</form>
 				</div>