Nostr Linked Data -- Relationship between Person and pubkey

I raised this issue here.  It would be good to nail down the relationship
between a Person and a pubkey and also bear in mind the work done on
integration with activitypub, and how a nostr pubkey can be added to a
mastodon profile, for example.

Right now I think that a Nostr Person is OWL range for a pubkey.  It may
need inverse or functional properties too.

There is also a need for a predicate linking ActivityPub or Solid to a
nostr pubkey string literal.  We might need to add npub in there too,
commonly used in clients.

https://github.com/nostrcg/schema/issues/8