Add Spear of Destiny shareware assets and update project files

- Added new asset files for Spear of Destiny shareware including AUDIOHED.SDM, AUDIOT.SDM, GAMEMAPS.SDM, MAPHEAD.SDM, VGADICT.SDM, VGAGRAPH.SDM, VGAHEAD.SDM, VSWAP.SDM, and documentation files (README.txt, SOD.DOC).
- Included necessary DLLs (SDL.dll, SDL_mixer.dll) for audio support.
- Updated pubspec.yaml to include the new assets directory for Spear of Destiny.
- Enhanced data versioning to recognize Spear of Destiny shareware in data_version.dart.
- Modified registry_resolver.dart to handle asset registry for Spear of Destiny shareware.
- Added license agreements for both id Software and MAME.

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

packages/wolf_3d_dart/lib/src/registry/registry_resolver.dart

@@ -47,8 +47,9 @@ class BuiltInAssetRegistryResolver implements AssetRegistryResolver {
       case DataVersion.version14Retail:
         return RetailAssetRegistry();
       case DataVersion.version14Shareware:
+      case DataVersion.spearOfDestinyShareware:
         return SharewareAssetRegistry(strictOriginalShareware: true);
-      case DataVersion.unknown:
+      case _:
         break; // fall through to GameVersion family check
     }