[RFE] Add -n option to crontab(5) to suppress mail when the run was successful

Issue

• We would like to see the "-n" feature in cronie as described at https://bugzilla.redhat.com/show_bug.cgi?id=1591763 as we treat it as very useful and valuable for us and our customers. Given cronie is a Red Hat fork of vixie-cron, Red Hat is also upstream of cronie, thus please perform such an implementation based on the OpenBSD reference implementation.