nix: use upstream gitlab-runner module

This migrates to the upstream gitlab-runner module and allows removing
the custom one \o/

nix/os/devices/vmd32387.contaboserver.net/configuration.nix

@@ -2,12 +2,10 @@
 
 {
   disabledModules = [
-    "services/continuous-integration/gitlab-runner.nix"
   ];
   imports = [
     ../../profiles/common/configuration.nix
     ../../modules/encryptedDisk.nix
-    ../../modules/gitlab-runner.nix
 
     ./system.nix
     ./hw.nix

nix/os/devices/vmd32387.contaboserver.net/pkg.nix

@@ -10,7 +10,15 @@
   };
   home-manager.users.steveej = import ../../../home-manager/configuration/text-minimal.nix { inherit pkgs; };
 
- services.hydra = {
+  nix.buildMachines = [
+    { hostName = "localhost";
+      system = "x86_64-linux";
+      supportedFeatures = ["kvm" "nixos-test" "big-parallel" "benchmark"];
+      maxJobs = 4;
+    }
+  ];
+
+  services.hydra = {
     enable = false;
     hydraURL = "http://localhost:3000"; # externally visible URL
     notificationSender = "hydra@${config.networking.hostName}.stefanjunker.de"; # e-mail of hydra service
@@ -20,18 +28,10 @@
     useSubstitutes = true;
   };
 
-  nix.buildMachines = [
-    { hostName = "localhost";
-      system = "x86_64-linux";
-      supportedFeatures = ["kvm" "nixos-test" "big-parallel" "benchmark"];
-      maxJobs = 4;
-    }
-  ];
-
   services.gitlab-runner = {
     enable = true;
 
-    packages = with pkgs; [
+    extraPackages = with pkgs; [
       bash
       gitlab-runner
       nix
@@ -39,18 +39,16 @@
       git-crypt
     ];
 
-    configFile = let
-      nixRunnerToken = "/etc/secrets/gitlab-runner/nix-runner.token";
-    in pkgs.writeText "config.toml" ''
-        concurrent = 2
-        check_interval = 0
-        [[runners]]
-          name = "nix-runner"
-          url = "https://gitlab.com"
-          token = "<% sed -z 's/[\n\s]//g' ${nixRunnerToken} %>"
-          executor = "shell"
-          shell = "bash"
-          [runners.cache]
-      '';
+    concurrent = 2;
+    checkInterval = 0;
+    services = {
+      nixRunner = {
+        executor = "shell";
+        runUntagged = true;
+        registrationConfigFile = "/etc/secrets/gitlab-runner/nix-runner.registration";
+        tagList = [ "nix" ];
+      };
+    };
+
   };
 }