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/emu/emu.cc

@@ -11,11 +11,11 @@
 #include "absl/debugging/failure_signal_handler.h"
 #include "absl/debugging/symbolize.h"
 #include "absl/status/status.h"
-#include "app/core/platform/sdl_deleter.h"
+#include "util/sdl_deleter.h"
 #include "app/emu/snes.h"
 #include "app/rom.h"
 
-using yaze::core::SDL_Deleter;
+using yaze::util::SDL_Deleter;
 
 int main(int argc, char **argv) {
   absl::InitializeSymbolizer(argv[0]);

src/app/emu/emulator.cc

@@ -4,7 +4,7 @@
 #include <fstream>
 #include <vector>
 
-#include "app/core/platform/file_dialog.h"
+#include "util/file_util.h"
 #include "app/core/window.h"
 #include "app/emu/cpu/internal/opcodes.h"
 #include "app/gui/icons.h"
@@ -316,7 +316,7 @@ void Emulator::RenderNavBar() {
   }
 
   if (open_file) {
-    auto file_name = core::FileDialogWrapper::ShowOpenFileDialog();
+    auto file_name = util::FileDialogWrapper::ShowOpenFileDialog();
     if (!file_name.empty()) {
       std::ifstream file(file_name, std::ios::binary);
       // Load the data directly into rom_data