logging for zync

[mccanne]

We should think through and implement how zync should do logging and change the various printf's to log calls. This will be used from orchestration and automation so these logs will be useful events in operational logging systems.

[philrz]

Some details on specific things one user wanted to see implemented here:

Is it possible to add some log when new data is receive from kafka in continuous mode? Actually data from kafka is write to zed lake but in my Zync container console (docker) I see nothing. I want to see something like old zync : number of row receive, commit id... something to show me that zync is really running and processing.