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/shared/actions/runner_edit.tmpl

@@ -5,7 +5,6 @@
 	<div class="ui attached segment">
 		<form class="ui form" method="post">
 			{{template "base/disable_form_autofill"}}
-			{{.CsrfTokenHtml}}
 			<div class="runner-basic-info">
 				<div class="field tw-inline-block tw-mr-4">
 					<label>{{ctx.Locale.Tr "actions.runners.status"}}</label>