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/team/invite.tmpl

@@ -13,7 +13,6 @@
 			</div>
 			<div class="extra content">
 				<form class="ui form" action="" method="post">
-					{{.CsrfTokenHtml}}
 					<button class="fluid ui primary button">{{ctx.Locale.Tr "org.teams.join"}}</button>
 				</form>
 			</div>