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
easier to maintain custom rules for non-system things like ACPI hotkeys.
/etc/devd.conf is already set up to check this directory, no change needed there.