The Provider needs some kind of "claim" mechanism for orphaned provider entries

[humanizersequel]

An "orphaned" provider entry is a provider entry whose record lives onchain, but for whatever reason, does not have a live correlating Provider node set up or running anywhere. This could be due to the provider node losing state, or the node becoming permanently inaccessible... I was going to write a list but actually that's it.

Since the Provider now inherits the Operator's indexing, it should be trivial for the frontend to display cards for entries whose ~provider-id note points to the node being used, but isn't actually configured on the backend. Then the user can just make that provider. Currently the user is prevented from making a provider that already exists, even if it's one they should in theory own.

It's possible this is already accounted for in which case @Gohlub you should just comment and close this issue. I wrote it after thinking that #69 might cause some migration problems (or just "don't cause migration issues").

[Gohlub]

An issue with this that immediately comes to my attention is the NFT for the namespace entry of the provider: we can't recapture ownership of it without the node owner returning the NFT to us: so we can't give the provider 'adoptee' the permission to mint anything under that namespace entry.