refactor: Introduce OverworldEntityRenderer for Enhanced Entity Visualization

- Added OverworldEntityRenderer class to separate entity rendering logic from OverworldEditor, improving maintainability and testability.
- Updated OverworldEditor to utilize the new entity renderer, removing legacy drawing functions for entrances, exits, items, and sprites.
- Enhanced initialization and drawing methods to streamline entity visualization and interaction within the editor.
- Updated CMake configuration to include the new renderer files, ensuring proper integration into the build system.

src/app/editor/editor_library.cmake

@@ -35,6 +35,7 @@ set(
   app/editor/overworld/map_properties.cc
   app/editor/graphics/gfx_group_editor.cc
   app/editor/overworld/entity.cc
+  app/editor/overworld/overworld_entity_renderer.cc
   app/editor/system/settings_editor.cc
   app/editor/system/command_manager.cc
   app/editor/system/extension_manager.cc