zfs.8: fix garbled options in a sample zfs send -R command line

MFC after:	5 days
move devd rules for zfs events into a separate file and fix stale event types

Also, extend with some new events.
Additionally, tag syslog messages with 'ZFS' instead of using explicit "ZFS: "
prefix in the messages themselves.

Tested by:	Daniel O'Connor <doconnor@gsoft.com.au>
MFC after:	8 days
Sponsored by:	HybridCluster