Remove PNG and ZLIB support from the project

- Eliminated all references to PNG and ZLIB dependencies in CMake configuration and project files.
- Updated documentation to reflect the removal of PNG support and related functionalities.
- Adjusted build scripts and source files to remove unused code related to PNG handling, ensuring a cleaner codebase.

src/app/editor/overworld/overworld_editor.cc

@@ -124,17 +124,7 @@ void OverworldEditor::Initialize() {
   });
   gui::AddTableColumn(toolset_table_, "##CopyMap", [&]() {
     if (Button(ICON_MD_CONTENT_COPY)) {
-#if YAZE_LIB_PNG == 1
-      std::vector<uint8_t> png_data = maps_bmp_[current_map_].GetPngData();
-      if (png_data.size() > 0) {
-        core::CopyImageToClipboard(png_data);
-      } else {
-        status_ = absl::InternalError(
-            "Failed to convert overworld map surface to PNG");
-      }
-#else
-      status_ = absl::UnimplementedError("PNG export not available in this build");
-#endif
+      status_ = absl::UnimplementedError("PNG export functionality removed");
     }
     HOVER_HINT("Copy Map to Clipboard");
   });