Motivation for this change

This partially fixes the Gitlab NixOS test. The module has had several required options added since the inception of this test, and they are now present. Gitlab also no longer serves on port 8080 on its own, but relies on a proxy-to-socket solution, which has also been added.

The test still times out even with extreme time limits on the gitlab service. The culprit is difficult to identify, but it should be possible to work on just that with this fix. I am able to run this on a libvirtd-deploy via nixops succesfully, so I am fairly confident that only the slowness in bundler/sidekiq needs to be addressed.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.