Save requested songs into a new playlist

[gCoreByte]

Requested by streamer.

Save all requested songs into a separate playlist, eg Twitch Requested Songs. This would allow the streamer to both link this album to chat as well as be able to save songs they liked after the stream. As there can only be a max of 10k songs per playlist, we should also check whether a song can be added. If not, we should probably delete the oldest song in that playlist.