Add nixpad configuration

The initial step of grouping lemp11 and t490 configuration, inspired by
https://github.com/mkellyxp/nixbook.

hosts/lemp11/configuration.nix

@@ -18,6 +18,8 @@
 
   desktop.media.makemkv.enable = true;
 
+  nixpad.enable = true;
+
   # Bootloader.
   boot = {
     loader = {
@@ -49,11 +51,8 @@
     vscodium
   ];
 
-  system.autoUpgrade.enable = true;
-
   environment.systemPackages = with pkgs; [
     fastfetch
     htop
-    libreoffice
   ];
 }

hosts/lemp11/services.nix

@@ -27,9 +27,6 @@
         layout = "gb";
         variant = "";
       };
-
-      desktopManager.cinnamon.enable = true;
-      displayManager.lightdm.enable = true;
     };
   };
 }

hosts/t490/configuration.nix

@@ -17,6 +17,8 @@
 
   desktop.dconf.enable = true;
 
+  nixpad.enable = true;
+
   boot = {
     loader = {
       systemd-boot = {
@@ -35,6 +37,4 @@
   '';
 
   networking.networkmanager.enable = true;
-
-  system.autoUpgrade.enable = true;
 }

hosts/t490/services/default.nix

@@ -26,10 +26,5 @@
     throttled.enable = true;
     thermald.enable = true;
     upower.enable = true;
-
-    xserver = {
-      desktopManager.cinnamon.enable = true;
-      displayManager.lightdm.enable = true;
-    };
   };
 }

modules/nixos/default.nix

@@ -4,5 +4,6 @@
     ./core
     ./desktop
     ./homelab
+    ./nixpad
   ];
 }

modules/nixos/nixpad/default.nix

@@ -0,0 +1,37 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.nixpad;
+in
+{
+  options.nixpad = {
+    enable = lib.mkEnableOption "Enable nixpad configuration";
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.xserver = {
+      enable = true;
+
+      desktopManager.cinnamon.enable = true;
+      displayManager.lightdm.enable = true;
+    };
+
+    programs.firefox.enable = true;
+
+    environment.systemPackages = with pkgs; [
+      git
+      libreoffice
+    ];
+
+    nix.gc = {
+      automatic = true;
+      dates = "Mon 4:00";
+      options = "--delete-older-than 30d";
+    };
+  };
+}