Add checker for app or games in disk

[realahmed7777]

Thanks for the great app, i do have suggestion, can you add a feature that check if the app or game yo added to stea library still exist on drive? sometimes i delete and app or game that i added to steam library but forget to remove it from the library. as the current implementation of the app check if an app is installed by viewing if its still in the steam library, also an option to delete the prefix data with the game or app folder will be good