Control Plane Machine Set Testing(4.15)

This Feature covers the pending tasks from OCPBU-16 to be covered in openshift-4.14. 

Goal: Control plane nodes in the cluster can be scaled up or down, lost and recovered, with no more importance or special procedure than that of a data plane node.

Problem: There is a lengthy special procedure to recover from a failed control plane node (or majority of nodes) and to add new control plane nodes.

Why is this important: Increased operational simplicity and scale flexibility of the cluster's control plane deployment.

See slack working group: #wg-ctrl-plane-resize