Favorites: Fix the save location + Enable the search feature
This merge request brings a fix to:
- The Favorite folders that are now saved in the caches folder of the AppleTV device as this is the only folder that is not systematically erased when the application is killed.
- The view controller used, that is now a
VLCSearchableServerBrowsingTVViewController
in order to enable the user to search for items while browsing the favorites on tvOS.
Closes #1809 (closed)