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/util/util.cmake

@@ -15,6 +15,8 @@ set(YAZE_UTIL_SRC
   util/flag.cc
   util/hex.cc
   util/log.cc
+  util/platform_paths.cc
+  util/file_util.cc
 )
 
 add_library(yaze_util STATIC ${YAZE_UTIL_SRC})