This patch adds consistent replication group capabilities for VNX
driver.
Supported operations:
* Create volume and add to replication group
* Add volume to existing replication group
* Enable replication on group
* Disable replication on group
* Fail over replication group back and forth
DocImpact
Implements: blueprint replication-cg-vnx
Change-Id: Iead8d2fd5581a70afb481239199fcbb1246aa27e
c52323babd