New linear datastore snapshot behavior for ALLOW_ORPHANS

[onenhansen]

Description
A new style of snapshots should be created to resolve an unhandled situation where snapshots are not dependent on each other, nor do they have child/parent relationships, but any younger snapshots are removed when you restore to a snapshot. For example, a disk has 3 snapshots ( Snap1, Snap2, Snap3 ). We can delete Snap2 without any issues since they are not related however if you revert back to Snap1, then Snap3 will disappear and Snap2 would disappear if you had not deleted it.

Use case
Some storage solutions may handle snapshots in this manner

Interface Changes
No major changes, this can be represented with the same style as ALLOW_ORPHANS="NO"

Progress Status

• Code committed
• Testing - QA
• Documentation (Release notes - resolved issues, compatibility, known issues)