Tracking story for backporting dual stream related work to 4.21. APIs etc. already exists, but MCO functionality is still open and will merge into 4.22. We would like to backport all feature functionality as one PR

List of PRs to backport:

• https://github.com/openshift/machine-config-operator/pull/5488
• https://github.com/openshift/machine-config-operator/pull/5476
• https://github.com/openshift/machine-config-operator/pull/5538
• https://github.com/openshift/machine-config-operator/pull/5535