Sister site to progarchives and jazzmusicarchives, we should add the same support:

• Other databases whitelist
• Artist pages (https://www.metalmusicarchives.com/artist/metallica)
• Album pages (https://www.metalmusicarchives.com/album/metallica/master-of-puppets)

I probably wouldn't bother adding handling for genre pages yet, because I'm not going to be using them at the moment. If we decide to use these we can always add genre support for all three sister pages.