Add sort options for the content of playlists

Feature request to add the sort options for the content of playlists.

The users would be able to :

• Sort the items of a playlist as they want and thus have a "Custom sort" (which is currently the only sort option available on both VLC-Android & VLC-iOS).
• Sort the items of a playlist by the same options as the collections (which would disable the possibility to perform a "custom sort" to avoid conflicts).