Proposed title of this feature request

Wait for volumes to detach before rebooting nodes

2. What is the nature and description of the request?

This request came out of this customer escalation: https://issues.redhat.com/browse/OCPBUGS-53165 

The immediate issue could not be resolved on Storage end. However, the MCO could provide a mechanism to wait until volumes to detach before rebooting.

That could mean something like: "the MCO for something to check for node.Status.VolumesAttached , and wait (with a timeout limit) for that field to be empty (which means something else has finished detaching volumes) before rebooting the node."

This is thought to exclusively be needed only by baremetal environments. In Cloud environments, a more robust storage/volume managment APIs which are decoupled from node's lifecycle are available.

3. Why does the customer need this? (List the business requirements here)

This mitigates a bug that a specific customer in a specific situation ran into (see bug).

4. List any affected packages or components.
MCO, Storage