MenuBar: Add entries to open the config and cache folders

Source/Core/DolphinQt/MenuBar.h

@@ -62,6 +62,8 @@ signals:
   void ChangeDisc();
   void EjectDisc();
   void OpenUserFolder();
+  void OpenConfigFolder();
+  void OpenCacheFolder();
 
   // Emulation
   void Play();
@@ -211,6 +213,8 @@ private:
   QAction* m_eject_disc;
   QMenu* m_backup_menu;
   QAction* m_open_user_folder;
+  QAction* m_open_config_folder;
+  QAction* m_open_cache_folder;
 
   // Tools
   QAction* m_wad_install_action;