The endpoint shows the known cluster nodes.

Create parent destroy() and make sure 'close' always is emitted,
child classes implement their own _destroy() logic.

Create a proper transport class for inter-cluster connection
redirects.

- Handle local and remote connections in the same way
- The Tunnel object represents both config and state.
  Config is written to persistent storage and state
  is kept in-memory.
- Fixes long-standing issues with tunnel disconnection

…face