Tracker: Consistency groups

[ShyamsundarR]

This issue is to serve as a tracker for items regarding consistency group support. Each item can be converted into an issue by itself and addressed.

Priority 1:

• Simplify the path to access the original PVC by implementing the new update to the CSI as outlined in this pull request once it is integrated into ceph-csi.
• Ensure Ramen controllers work on setups without the VGSnap CRDs

Priority 2:

• Provide a common label CG name, such as ramendr.openshift.io/cg-label. If the user labels the PVC with that label, then the PVC label value for CG should be the combination of ramendr.openshift.io/consistency-group: storageId + cg-label. This allows users to further subdivide their PVCs into CGs.
• Ensure that CG creation (or otherwise) is only effective the first time VRG is deployed ref
• Extend drenv to add required VolGroupSnapshot setups
• Extend drenv to add required VolGroupReplication setups
• Extend e2e to test volume groups based protection
• Proposal: Testing consistency group based replication and DR protection #1508
• Add status reflecting volumes that are grouped
• Some basic documentation on volume groups support from a user consumption perspective

Priority 3:

• Ensure replicationID match is found if CG is desired ref
• Address optimizations in processVRG to keep it simpler when distributing PVCs across VR/VS ref