Improve delegate dataset mount option and snapshots
Improve delegate dataset mount option and snapshots

- verify if zfs mountpoint is already configured
- switch snapshot config to 2day=>8hour,14day=>1day,1year=>1month,10year=>1year
- use znapzend only if delegate dataset is used

skylime/mi-core-kumquat,skylime/mi-core-kumquat,skylime/mi-core-kumquat,skylime/mi-core-kumquat