Remove legacy MediaLibraryKit

The current versions including the upcoming 3.3.0 release still include the legacy MediaLibraryKit that was replaced by VLCMediaLibraryKit in version 3.2. It should eventually be removed. Users updating from 3.1 to 3.3 should already be rare and even more for future releases.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information