Setup ZFS snapshots for home volumes

Summary:
This allows to go back in time to recover or compare files.

Especially useful on devservers, it can be useful too on other servers,
and allow an unified setup for FreeBSD machines.

Fixes T1312.

Test Plan: Tested on WindRiver

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1312

Differential Revision: https://devcentral.nasqueron.org/D2906