feat: artist sync

[driessamyn]

Add support for synchronising followed artists

follow-up from : #150

[gusfraser]

Oops I didn't see this, you beat me to it! :-) Also implemented it in my fork because I needed it.

[yodaluca23]

I think it should print and write to a file (like albums and playlists currently do) the not found artists, so that users can go through and try manually finding missing artists.

[driessamyn]

I think it should print and write to a file (like albums and playlists currently do) the not found artists, so that users can go through and try manually finding missing artists.

I had further developmed my fork as I didn't get any feedback on my proposed PRs.
I created a new, 3rd, PR that includes all changes, including a consolidated "missing items" file that list everything that was missed across syncing playlists, artitsts, songs.

#159

I'm happy to get my changes in whichever format necessary to merge. Until then, I'll continue to maintain my fork.