FollowRemoteRequest
    person   PersonId
    target   FedURI
    recip    FedURI Maybe
    public   Bool
    activity OutboxItemId

    UniqueFollowRemoteRequest person target
    UniqueFollowRemoteRequestActivity activity

FollowRemote
    person PersonId
    recip  RemoteActorId -- actor managing the followed object
    target FedURI        -- the followed object
    public Bool
    follow OutboxItemId
    accept RemoteActivityId

    UniqueFollowRemote person target
    UniqueFollowRemoteFollow follow
    UniqueFollowRemoteAccept accept