swh-graph Add java process port monitoring
swh-graph is now based on a grpc process and a java process.
For some reasons (to determine) the java process can crash and let the grpc part alone without monitoring notification
We should be notified by the monitoring if nothing is listening on the port
(we should also think to use a port outside the ephemeral range as nothing can guaranty the port is free when the service starts)
Migrated from T4471 (view on Phabricator)