refactor: Restructure file dialog handling and introduce utility classes

- Updated file dialog references across the application to utilize a new `util::FileDialogWrapper` for consistent file handling.
- Refactored existing code to replace direct calls to `core::FileDialogWrapper` with the new utility class, enhancing modularity and maintainability.
- Introduced `util::PlatformPaths` for cross-platform directory management, ensuring consistent access to user directories and application data paths.
- Added new utility functions for file operations, improving the overall file handling capabilities within the application.
- Updated CMake configurations to include new utility source files, streamlining the build process.

src/app/core/core_library.cmake

@@ -10,13 +10,11 @@ set(
 if (WIN32 OR MINGW OR (UNIX AND NOT APPLE))
   list(APPEND YAZE_APP_CORE_SRC
     app/core/platform/font_loader.cc
-    app/core/platform/file_dialog.cc
   )
 endif()
 
 if(APPLE)
     list(APPEND YAZE_APP_CORE_SRC
-      app/core/platform/file_dialog.cc
       app/core/platform/file_dialog.mm
       app/core/platform/app_delegate.mm
       app/core/platform/font_loader.cc