refactor(ops/modules): Rename git-serving -> josh

cgit has its own module now

Change-Id: I9b4cc322374517b8bd3db43345831e2bf43c4bb1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5295
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>

ops/modules/josh.nix

@@ -0,0 +1,33 @@
+# Configures the public josh instance for serving the depot.
+{ config, depot, lib, pkgs, ... }:
+
+let
+  cfg = config.services.depot.josh;
+in
+{
+  options.services.depot.josh = with lib; {
+    enable = mkEnableOption "Enable josh for serving the depot";
+
+    port = mkOption {
+      description = "Port on which josh should listen";
+      type = types.int;
+      default = 5674;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    # Run josh for the depot.
+    systemd.services.josh = {
+      description = "josh - partial cloning of monorepos";
+      wantedBy = [ "multi-user.target" ];
+      path = [ pkgs.git pkgs.bash ];
+
+      serviceConfig = {
+        DynamicUser = true;
+        StateDirectory = "josh";
+        Restart = "always";
+        ExecStart = "${depot.third_party.josh}/bin/josh-proxy --no-background --local /var/lib/josh --port ${toString cfg.port} --remote https://cl.tvl.fyi/";
+      };
+    };
+  };
+}