Process collaborative playlists

[brandon-rogers]

I have a few collaborative playlists (of which I am the original owner/creator) that spotify-dedup doesn't see/process.

[JMPerez]

Unfortunately, modifying a collaborative playlist is an operation that is not supported by the Spotify Web API (see scopes). Since reading is possible, I will implement duplicates-checking and will show a message, encouraging to delete them from a Spotify client.

This is similar to how starred playlists work.