Refactor audio module to use built-in music and sound effect identifiers

- Introduced BuiltInMusicModule and BuiltInSfxModule to replace RetailMusicModule and RetailSfxModule.
- Updated RetailAssetRegistry and SharewareAssetRegistry to utilize the new built-in modules.
- Removed deprecated MusicKey and SfxKey classes, replacing them with Music and SoundEffect enums for better clarity and maintainability.
- Adjusted music and sound effect resolution methods to align with the new structure.
- Updated audio playback methods in WolfAudio and FlutterAudioAdapter to accept the new Music and SoundEffect types.
- Refactored tests to accommodate changes in audio event handling and ensure compatibility with the new identifiers.

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

packages/wolf_3d_dart/test/rendering/pushwall_renderer_test.dart

@@ -45,7 +45,7 @@ void main() {
                   wallGrid: wallGrid,
                   areaGrid: List.generate(64, (_) => List.filled(64, -1)),
                   objectGrid: objectGrid,
-                  musicIndex: 0,
+                  music: Music.level01,
                 ),
               ],
             ),