lastHeight/blockSig/blockTimestamp, etc. moved from PeerData/repository
to Peer as it's transient so no need to store in repository.
Repository now keeps track of when/who added peer, e.g. API/INIT/another peer.
API calls DELETE /peers and DELETE /peers/known also disconnect peer
as well as deleting from repository.
Connection timestamp now reported by API call GET /peers
Some repository-updating code removed from Network/Controller as no
longer needed.
Removed obsolete Controller.hasShorterBlockchain predicate.
fc82bcaf49