Crono clean

[SaimonL]

This is not a bug but rather a feature request.

The database table "crono_jobs" over time becomes flooded with old cron jobs and massive logs.
It would be nice if I could do something like cap staging crono:clean which will truncate the table "crono_jobs" and restart crono (which already re-populates the table with the latest cron jobs).

At the moment I have to ssh to the server and clear the table manually. I do not care about the old cron logs or the recent cron logs in the database.

Thanks