Set Application controller default URL options to ensure all url_for calls are consistent
What does this MR do?
This MR sets the app controller's default_url_options so that all url_for calls are consistent.
Are there points in the code the reviewer needs to double check?
Setting these options may simplify url_for calls that load the GitLab options already. I did not want to touch existing code yet. I'm also not sure if there are other options that need to be included.
Why was this MR needed?
If you run GitLab behind a reverse proxy or in a Docker container, you don't want a user to be seeing the local IP and port on which GitLab is running (e.g. 192.168.1.1:8080). Right now there are places where this internal data is leaked (e.g. see the URL in Profile Settings -> Account -> Username; this uses user_url).