Add GnuPG module

modules/nixos/gpg.nix

@@ -0,0 +1,20 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  options = {
+    sydnix.gpg = {
+      enable = mkEnableOption "GnuPG";
+    };
+  };
+
+  config = mkIf config.sydnix.gpg.enable {
+    programs.gnupg.agent = {
+      enable = true;
+      enableSSHSupport = true;
+    };
+
+    environment.systemPackages = [ pkgs.gnupg ];
+  };
+}