[Tagging] Relation for multi-part artworks

[Andy Mabbett]

I hope to find consensus for how to tag artworks with multiple parts,
as a relation. Here are some examples:

Nine 'Moonstones', including:

   https://www.openstreetmap.org/node/2501118658
   https://www.openstreetmap.org/node/2501118659
   https://www.openstreetmap.org/node/2501118660
   https://www.openstreetmap.org/node/2501127353

   https://en.wikipedia.org/wiki/Lunar_Society_Moonstones

Set of three murals at Handsworth, Birmingham:

   https://www.openstreetmap.org/node/7112445731
   https://www.openstreetmap.org/node/7112445732
   https://www.openstreetmap.org/node/7112445733

Set of statues in Porto:

   https://www.openstreetmap.org/node/2996821310

   https://commons.wikimedia.org/wiki/File:People_looking_the_sky_%28Faro_district%29.JPG

We could use relation_type:set (which I used for the Moonstones) or
define a new relation_type:artwork

Thoughts?

--
Andy Mabbett
@pigsonthewing
http://pigsonthewing.org.uk