Auto reconfigure Drone on reconnect

[pstavirs]

If Drone is stopped and restarted (or restarted after a crash), Ostinato should reapply the last configuration automatically.

While this might be a good default behavior, there may be cases where this is not desired. For those cases, a delete/add portgroup can be a workaround to prevent this behavior (or alternatively, close and reopen GUI).

The atConnectConfig infra implemented for session files, can be re-used to implement this.