Avoid OpenShift - Node reboot when applying changes on image.config.openshift.io/cluster

1. Proposed title of this feature request
Avoid OpenShift - Node reboot when applying changes on image.config.openshift.io/cluster

2. What is the nature and description of the request?
Applying changes on image.config.openshift.io/cluster based on https://docs.openshift.com/container-platform/4.9/openshift_images/image-configuration.html will always trigger OpenShift - Node reboot to apply them. Those are rather unexpected OpenShift - Node reboots (expected because it's done via MachineConfig) due to the nature of the change.

Depending on the environment, there may be frequent changes required on the image.config.openshift.io/cluster and it's therefore the question whether the OpenShift - Node reboot could be skipped when applying changes in image.config.openshift.io/cluster or at least for specific changes that can be done without restarting services, etc.

3. Why does the customer need this? (List the business requirements here)
Since image.config.openshift.io/cluster may require frequent changes depending on the environment it would help if the OpenShift - Node reboot can be skipped when possible to prevent too much disruption in busy environments.

4. List any affected packages or components.
OpenShift Container Platform 4 - Image Registry
OpenShift Container Platform 4 - MachineConfig