added extra to settings

extra/default.nix

@@ -1,8 +1,12 @@
+{ lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
 {
-    imports = [
-        ./bluray.nix
-        ./dvd.nix
-        ./yubikey.nix
-        ./wireguard.nix
-    ];
+    # Optionally import modules for non-essential extras
+    imports =
+        lib.optionals settings.hardware.yubikey.enable [ ./yubikey.nix ]
+        ++ lib.optionals settings.dvd [ ./dvd.nix ]
+        ++ lib.optionals settings.bluray [ ./bluray.nix ]
+        ++ lib.optionals settings.networking.wireguard [ ./wireguard.nix ];
 }

extra/yubikey.nix

@@ -2,11 +2,12 @@
 
     services.pcscd.enable = true; # enable support for smart cards
 
-    environment.systemPackages = with pkgs; [
-        # Yubikey stuff
-        yubioath-flutter    # Yubico authentictor app for managing accounts
-        yubikey-manager     # CLI tool for ykman
-        yubikey-manager-qt  # GUI tool for ykman
-        pcsclite
-    ];
+    environment.systemPackages = with pkgs; [ pcsclite ]
+        # Yubico authentictor app for managing accounts
+        ++ (lib.optionals settings.hardware.yubikey.authenticator [ yubioath-flutter ])
+        # ykman CLI and Qt-GUI
+        ++ (lib.optionals settings.hardware.yubikey.ykman [
+            yubikey-manager     # CLI tool for ykman
+            yubikey-manager-qt  # GUI tool for ykman
+        ]);
 }

settings.nix

@@ -1,7 +1,23 @@
 {
     hardware = {
+        # support for GPUs
         amdgpu = true;
         intelgpu = false;
         nvidiagpu = false;
+
+        # support for yubikey and additional software
+        yubikey = {
+            enable = true;
+            # additional software
+            ykman = false;
+            authenticator = true;   # flutter yubico authenticator
+        };
+    };
+
+    dvd = true;     # enable DVD decryption + ripping via Handbrake
+    bluray = true;  # enable Bluray decryption (requires additional setup)
+
+    networking = {
+        wireguard = true;   # enable wireguard protocol
     };
 }