Export/import shouldn't create bogus Person records
Summary: When you export a Space and import it again, you get all the Person records as Members of the Space. But that's broken: they aren't actually Members, and they don't have all their contents, so those records are actually dead.
The easy solution here would be to not export them at all. But there is an additional consideration: _creator only half-works in the imported Space. If this user joins the new Space, then _creator gets hooked up properly to the new Identity. But if not, it doesn't display anything!
The issue there is that, since the Person to Identity Link Property is internal, its value isn't being exported, so we are getting essentially empty Person records: they show up as Members, but they are broken, and can't ever be fixed. When and if the user joins again, a second Person gets added, which is correct, but the old one hangs around.
In theory, we should probably:
- Fix the Person export so that it is actually exporting the IdentityId.
- Fix the import so that Person records get shunted off to some other ImportedPerson type, that doesn't get counted as Members.
- When looking someone up by ID in LocalPerson, we use ImportedPersons as a fallback if and only if a Member isn't found, so that they will display in cases like
_creator and Conversations.
