Refactor graphics sheet management with singleton class

Refactor the handling of graphics sheets by introducing a singleton class `GraphicsSheetManager`. This centralizes the management of graphics sheets, replacing direct access through the `Rom` object. Key changes include:

- Updated various methods across multiple classes to use `GraphicsSheetManager::GetInstance()` for accessing and manipulating graphics sheets.
- Introduced standalone functions `LoadLinkGraphics`, `LoadAllGraphicsData`, and `SaveAllGraphicsData` for loading and saving graphics data.
- Refactored the `Rom` class to remove methods and member variables related to graphics sheet management.
- Updated `OverworldEditor` to use `std::array` for `maps_bmp_` and added error handling for `std::bad_alloc` exceptions.
- Improved code modularity and error handling throughout the application.

src/app/zelda3/dungeon/object_renderer.cc

@@ -102,7 +102,7 @@ void DungeonObjectRenderer::UpdateObjectBitmap() {
     int x = column * 8;
     int y = row * 8;
 
-    auto sheet = rom()->mutable_gfx_sheets()->at(vram_.sheets[sheet_number]);
+    auto sheet = GraphicsSheetManager::GetInstance().mutable_gfx_sheets()->at(vram_.sheets[sheet_number]);
 
     // Copy the tile from VRAM using the read tile_id
     sheet.Get8x8Tile(tile_id, x, y, tilemap_, tilemap_offset);