Integrate hummelberg desktop configuration

defaults/desktop/desktop-environment.nix

@@ -0,0 +1,53 @@
+{ config, pkgs, lib, ... }: {
+
+  environment.systemPackages = with pkgs;
+    [ # Utilities
+      freetype
+      light
+      xorg.xbacklight
+      feh
+      redshift
+      numlockx # TODO: Does this work?
+      lxappearance
+    ] ++ [ # Networking
+      gnome3.networkmanager-openconnect
+    ] ++ [ # Various
+      xfce.thunar
+      xfce.thunar-archive-plugin
+      xfce.xfce4-appfinder # xfce.thunar-volman # needed?
+      xfce.terminal
+      gnome3.gnome-screenshot
+      pinentry-gtk2 # Required by gnupg
+    ];
+
+  programs = {
+    gnome-terminal.enable = false;
+    geary.enable = false;
+    light.enable = true;
+
+    gnupg.agent.pinentryFlavor = "gtk2";
+
+    dconf.enable = true;
+  };
+
+  services.gnome3 = {
+    # TODO: Do this manually and not all at once.
+    core-utilities.enable = true;
+
+    gnome-keyring.enable = true;
+    evolution-data-server.enable = true;
+    gnome-online-accounts.enable = true;
+
+    sushi.enable = false;
+  };
+
+  services.gvfs.enable = true;
+
+  services.flatpak.enable = true;
+  xdg.portal = {
+    enable = true;
+    gtkUsePortal = true;
+    extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
+  };
+
+}