Use Gitea over GitLab

Gitea simply offers better performance. I wasn't using all of GitLab's
features anyway, and while the missing CI is annoying, I hadn't
previously managed to set this up anyway, and it can be easily
replaced by something a bit more dedicated than GitLab's
implementation.

This should hopefully allow me to host git repositories without
compromising on memory/CPU time available to other services.

etc/nixos/configuration.nix

@@ -12,7 +12,7 @@
     # and set inside the docker-containers set, instead of setting the
     # docker-containers set here.
     ./services/nginx.nix
-    ./services/gitlab.nix
+    ./services/gitea.nix
     ./services/nextcloud.nix
     ./services/tlaternet.nix
   ];
@@ -30,7 +30,7 @@
         80
         443
         2222
-        3022
+        2221
       ];
     };
   };