mv mullvad to module

modules/nix/vpn/mullvad.nix

@@ -0,0 +1,18 @@
+{  lib, config, pkgs, ... }:
+let
+  inherit (lib) mkIf mkOption types;
+in
+{
+  options.smayzy.mullvad.enable = mkOption {
+    type = types.bool;
+    default = false;
+    description = "mullvad's software";
+  };
+
+  config = mkIf config.smayzy.mullvad.enable {
+    environment.systemPackages = with pkgs; [
+      mullvad-vpn
+      mullvad-browser
+    ];
+  };
+}