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>

tests/integration/release_test.go

@@ -28,7 +28,6 @@ func createNewRelease(t *testing.T, session *TestSession, repoURL, tag, title st
 	assert.True(t, exists, "The template has changed")
 
 	postData := map[string]string{
-		"_csrf":      htmlDoc.GetCSRF(),
 		"tag_name":   tag,
 		"tag_target": "master",
 		"title":      title,