XtremIO add support for create CG from CG src

XtremIO add support for create CG from CG src

The method of creating CG from source was extended to support
create CG from other CG, this patch adds this capability for XtremIO.

The driver will:
1. Take an XtremIO snapshot of the source CG.
2. Renames the volumes of the snapset to fit Cinder IDs.
3. Create a new CG with the renamed volumes.

DocImpact: update capabities
Change-Id: I3ce791cf718f45c29d87e133eeebd6c68d340b0d
Implements: blueprint xtremio-cg-from-cg