Apps, refactor, clean up, remove librewolf

Refactors to use app.nix for easier extension.

Removes librewolf from host, as it makes more sense on the user every
time.

nixosModules/apps/inputremapper/app.nix

@@ -0,0 +1,11 @@
+{ config, lib, ... }:
+
+{
+  options.input-remapper = {
+    enable = lib.mkEnableOption "Enables input-remapper";
+  };
+
+  config = lib.mkIf config.input-remapper.enable {
+    services.input-remapper.enable = true;
+  };
+}