Create contrib scripts for lvm snapshots

[reaperzn]

Please create the following scripts for auter to create an lvm snapshot:

lvm-snap.pre-apply

Should take the following actions:

• Check if lvm is in use for the root filesystem
• Check if there is a reasonable amount of free unallocated space in the VG
• Check if there are already snapshots created (We probably don't want to allow multiple snapshots to be automatically created)
• If all checks are passed then create a new snapshot with a descriptive name associating it with auter