Endpoints to query and manage Drakov instances

[yakovkhalinsky]

Should add some endpoints to allow querying and management of running Drakov instances.

To this end, we will need to add an express server and specify a port for it to run on.

Possible endpoings:

/instances - get list of running Drakov instances
/instances/{drakov instance id} info about the Drakov instance
/instances/{drakov instance id}/start start the Drakov instance (if not already running)
/instances/{drakov instance id}/stop stop the Drakov instance
/instances/{drakov instance id}/restart restart the Drakov instance