Major config overhaul: use custom modules, setup for multi-host config, and less boilerplate

modules/user/flatpak/default.nix

@@ -0,0 +1,22 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.userSettings.flatpak;
+in {
+  options = {
+    userSettings.flatpak = {
+      enable = lib.mkEnableOption "Enable flatpak support";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    home.packages = [ pkgs.flatpak ];
+    home.sessionVariables = {
+      XDG_DATA_DIRS = "$XDG_DATA_DIRS:/usr/share:/var/lib/flatpak/exports/share:$HOME/.local/share/flatpak/exports/share"; # lets flatpak work
+    };
+
+    #services.flatpak.enable = true;
+    #services.flatpak.packages = [ { appId = "com.kde.kdenlive"; origin = "flathub";  } ];
+    #services.flatpak.update.onActivation = true;
+  };
+}