added dedicated focusrite scarlett, appimage modules, modified cloud

these new modules include only packages, no other configuration. maybe
later but none currently

modules/apps/appimage.nix

@@ -0,0 +1,19 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+with lib; let
+  cfg = config.appimage;
+in {
+  options.appimage = {
+    enable = mkEnableOption "AppImage support";
+  };
+  config = mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [
+      appimageupdate
+      appimage-run
+    ];
+  };
+}