nixos/openvpn3: add enable option

nixos/modules/module-list.nix

@@ -197,6 +197,7 @@
   ./programs/npm.nix
   ./programs/noisetorch.nix
   ./programs/oblogout.nix
+  ./programs/openvpn3.nix
   ./programs/pantheon-tweaks.nix
   ./programs/partition-manager.nix
   ./programs/plotinus.nix

nixos/modules/programs/openvpn3.nix

@@ -0,0 +1,33 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.openvpn3;
+in
+{
+  options.programs.openvpn3 = {
+    enable = mkEnableOption "the openvpn3 client";
+  };
+
+  config = mkIf cfg.enable {
+    services.dbus.packages = with pkgs; [
+      openvpn3
+    ];
+
+    users.users.openvpn = {
+      isSystemUser = true;
+      uid = config.ids.uids.openvpn;
+      group = "openvpn";
+    };
+
+    users.groups.openvpn = {
+      gid = config.ids.gids.openvpn;
+    };
+
+    environment.systemPackages = with pkgs; [
+      openvpn3
+    ];
+  };
+
+}