Connection actor takes care of establishing a connection to the maker and is
monitoring its status.
The connection actor:
- listens for periodically sent heartbeat messages from the maker,
- publish the maker status on a watch::channel feed outside TakerActorSystem,
- observe changes on the watch channel and shut down Rocket if maker goes offline
Note: this is a stepping stone resulting in temporary behaviour. Eventually,
we'd want to support reconnecting to the maker as well as operating the
taker without the maker being online (with a limited set of actions).
Co-authored-by: Thomas Eizinger <thomas@eizinger.io>