flake: rework modules folder structure

modules/nixos/programs/tuigreet.nix

@@ -0,0 +1,23 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+{
+  options.settings.programs.tuigreet = {
+    enable = lib.mkEnableOption "enables the tuigreet greeter";
+  };
+
+  config = lib.mkIf config.settings.programs.tuigreet.enable {
+    services.greetd = {
+      enable = true;
+      settings = {
+        default_session = {
+          command = "${pkgs.greetd.tuigreet}/bin/tuigreet -t -g \"Haii! :3\" --theme \"container=black;input=lightBlue;prompt=green;greet=magenta;border=blue\"";
+          user = "greeter";
+        };
+      };
+    };
+  };
+}