Federation with NeoDB

[chris-y]

Is your feature request related to a problem? Please describe.
Sort of. It isn't possible to follow (or be followed by) NeoDB users, and get books, reviews, comments federated like you can with other Bookwyrm users.

Describe the solution you'd like
Books (and only books, as NeoDB has other content on it) should be able to be imported from NeoDB instances, and NeoDB users should be able to be followed and have their reading, (book) comments and (book) reviews federated. This should also work back the other way so NeoDB users can see Bookwyrm activity.

Describe alternatives you've considered
On the Bookwyrm side, I can't see any feasible alternative.

Additional context
Originally raised here, but realised afterwards that this needs to be flagged here too:
neodb-social/neodb#725

Information about NeoDB is at NeoDB.net