Moved data types to its own package and added empty synth package

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_data/lib/src/wolfenstein_loader.dart

@@ -1,9 +1,9 @@
 import 'dart:typed_data';
 
-import 'classes/game_version.dart';
-import 'classes/wolfenstein_data.dart';
 // --- The Magic Conditional Import ---
 // If dart:io is available, use the real scanner. Otherwise, use the stub.
+import 'package:wolf_3d_data_types/wolf_3d_data_types.dart';
+
 import 'io/discovery_stub.dart'
     if (dart.library.io) 'io/discovery_io.dart'
     as platform;