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/org/settings/options_dangerzone.tmpl

@@ -47,7 +47,6 @@
 			</ul>
 		</div>
 		<form class="ui form form-fetch-action" action="{{.Link}}/visibility" method="post">
-			{{.CsrfTokenHtml}}
 			<input type="hidden" name="current_visibility" value="{{.CurrentVisibility}}">
 			<div class="tw-flex tw-flex-col tw-gap-3">
 				<label>{{ctx.Locale.Tr "org.settings.visibility"}}</label>
@@ -85,7 +84,6 @@
 			</ul>
 		</div>
 		<form class="ui form form-fetch-action" action="{{.Link}}/rename" method="post">
-			{{.CsrfTokenHtml}}
 			<div class="field">
 				<label>
 					{{ctx.Locale.Tr "org.settings.name_confirm"}}
@@ -124,7 +122,6 @@
 			</ul>
 		</div>
 		<form class="ui form form-fetch-action" action="{{.Link}}/delete" method="post">
-			{{.CsrfTokenHtml}}
 			<div class="field">
 				<label>
 					{{ctx.Locale.Tr "org.settings.name_confirm"}}