Qt: Add automatic download of redump disc database for game list

src/duckstation-qt/gamelistsettingswidget.h

@@ -30,6 +30,8 @@ protected:
   void resizeEvent(QResizeEvent* event);
 
 private:
+  bool downloadRedumpDatabase(const QString& download_path);
+
   QtHostInterface* m_host_interface;
 
   Ui::GameListSettingsWidget m_ui;