GitLab

Backport #21619 .

A patch to #17335.

Just like AppPath, Gitea writes its own CustomConf into git hook scripts
too. If Gitea's CustomConf changes, then the git push may fail.
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>