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/editor/upload.tmpl

@@ -7,7 +7,6 @@
 			{{template "repo/view_file_tree" .}}
 			<div class="repo-view-content">
 				<form class="ui comment form form-fetch-action" method="post" action="{{.CommitFormOptions.TargetFormAction}}">
-					{{.CsrfTokenHtml}}
 					{{template "repo/editor/common_top" .}}
 					<div class="repo-editor-header">
 						{{template "repo/view_file_tree_toggle_button" .}}