Easier discoverability for OAuth settings

I recently configured a Grafana server to use GitLab as an OAuth authentication provider. Doing so required getting a few API endpoints which required some work to discover.

Proposal

The GitLab pages which manage OAuth tokens would have a block specifying the URLs using the server's canonical URL — for example, this could be a basic table like this:

Purpose	URL
OAuth Authorization	https://example.org/oauth/authorize
OAuth Token	https://example.org/oauth/token
OpenID UserInfo	https://example.org/api/v4/user

Use cases

This would help anyone who isn't intimately familiar with GitLab's URL schema and is trying to translate terms from the documentation of a third-party application being integrated.

Constructing the URLs from the server's canonical hostname would avoid issues from users attempting to construct them manually but forgetting HTTPS vs. HTTP, adding double slashes, etc.