Add pretty basic Hyprland config to piplup.

In case I want to use it, though I don't imagine doing so soon.

system/piplup/gui-hyprland.nix

@@ -0,0 +1,17 @@
+{
+  # Mostly from https://wiki.hyprland.org/Nix/Hyprland-on-NixOS/
+  programs.hyprland.enable = true; # enable Hyprland
+
+  environment.systemPackages = [
+    # ... other packages
+    pkgs.kitty # required for the default Hyprland config
+  ];
+
+  # Optional, hint Electron apps to use Wayland:
+  # environment.sessionVariables.NIXOS_OZONE_WL = "1";
+
+
+  # If your themes for mouse cursors, icons or windows don’t load correctly, see
+  # the relevant section in Hyprland on Home Manager.
+  # Which is likely https://wiki.hyprland.org/Nix/Hyprland-on-Home-Manager/#faq
+}