Until now I've managed to avoid having to implement this piece quite
easily. The only temptation to implement it has been pseudo-client
features, which are basically just a workaround until Vervis gets a
separate client app.
But now, Person actors need to be able to automatically send
delegator-Grants when they receive a direct-Grant from a resource they
either asked to Join or got an Invite to. So, this creates a need to
track these joins and invites on the server side.
I'm not checking the exact minimal pieces necessary for
delegator-Grants. Instead, I'm starting a full implementation of the
person-side of Collab records (AKA direct-Grants), called Permit
records. This will also allow very convenient display of these Grants
and the extensions received through them, as well as UI buttons such as
accepting/rejecting a received Join or Invite.
