Only add first artist to the artist id3 tag

[skerit]

Requested Feature

When downloading songs that contain multiple artists, spotdl always creates files with an artist tags like:
Dua Lipa/Troye Sivan

I only care about the main artist. The other artists are often also attributed in the title tag (in this case Physical (feat. Troye Sivan))

The issue here is that there is no artist named "Dua Lipa/Troye Sivan", and it's just polluting my database and my last.fm scrobbles.

Possible implementation

Add an option to only add the first artist.