Is there an existing issue or pull request for this?

• I have searched the existing issues and pull requests

Feature description

Overriding the API URL for remotes is only possible via environment variables, e.g. GITLAB_API_URL. This is not very convenient.

This can be doable via config as well.

Desired solution

[remote.gitlab]
api_url="https://gitlab.archlinux.org/api/v4"
owner = "archlinux"
repo = "arch-repro-status"

Alternatives considered

None.

Additional context

No response