Support upgrade rollback

Proposed title of this feature

config update control

What is the nature and description of the request

Require the MCO continue to use a rendered config of the previous Y version of openshift understands until the next Y. For example, ignition spec bumps to 4.y-1 should be 2-way compatibility to support rollbacks.

Why does the customer need this?

Customers need to be able to rollback in the case of hung upgrades or emergency upgrades. (See screenshot of a previous bugzilla discussion around this.)

List any affected packages or components.

MCO, possibly RHCOS