WX: HiDPI: ISOProperties

And related ARCodeAddEdit/PatchAddEdit.

Change ISOFile to use wxImage instead of wxBitmap since bitmaps require
a screen context and banner images have a fixed resolution.

Source/Core/DolphinWX/GameListCtrl.h

@@ -70,6 +70,7 @@ private:
   std::vector<int> m_FlagImageIndex;
   std::vector<int> m_PlatformImageIndex;
   std::vector<int> m_EmuStateImageIndex;
+  std::vector<int> m_utility_game_banners;
   std::vector<std::unique_ptr<GameListItem>> m_ISOFiles;
 
   void ClearIsoFiles() { m_ISOFiles.clear(); }