Connections to a specific peer, or to all peers, can be closed and the peer information removed from the peer store. This can be useful to help determine if the presence/absence of a connection to a peer is affecting behavior. Be aware that purging a connection is inherently racey as it is possible for the peer to reestablish a connection at any time following a purge.

- `http://$RAINBOW_CTL_LISTEN_ADDRESS/mgr/purge?peer=<peer_id>` purges connection and info for peer identifid by peer_id
- `http://$RAINBOW_CTL_LISTEN_ADDRESS/mgr/purge?peer=all` purges connections and info for all peers
- `http://$RAINBOW_CTL_LISTEN_ADDRESS/mgr/peers` returns a list of currently connected peers

Closes #193

Co-authored-by: Marcin Rataj <lidel@lidel.org>