Feature Request: Generate config without home-manager

[minego]

I'd really like to be able to use this module to generate my niri config, but I don't use home manager... I currently am doing this with: ``` nixpkgs.overlays = [ niri.overlays.niri

				(_final: _prev: {
					# Modify the niri startup command to point it to the
					# config file
					niri-unstable = _prev.niri-unstable.overrideAttrs (final: prev: {
						postFixup = ''
							${prev.postFixup}

							substituteInPlace $out/share/systemd/user/niri.service --replace "--session" "--session -c ${./niri.kdl}"
							'';
					});
				})
			];

			programs.niri.enable			= true;
			programs.niri.package			= pkgs.niri-unstable;

I'd like to be able to use this flake to generate my `niri.kdl` file though. That would make it a lot easier to make tweaks for specific machines, etc.

Is it possible to do that, and then use the output in my overlay to point to that derivation?