1. Proposed title of this feature request
Have control over the settings of maxUnavailable
2. What is the nature and description of the request?
This is a catch all rfe to leverage upon work already done for setting maxUanavailable to an explicit value of 10%
  - ds/tuned https://issues.redhat.com/browse/OCPBUGSM-15168 
  - ds/node-exporter  https://issues.redhat.com/browse/OCPBUGSM-15166
  - ds/machine-config-deamon https://issues.redhat.com/browse/OCPBUGSM-15170
   Having the discretion to set this to a higher value 
3. Why does the customer need this? (List the business requirements here)
 For some of his clusters customer prefers having the upgrade during downtime due to application / client limitations failing during an upgrade.
Hence target is to minimize cluster upgrade time as much as possible - as availability is not a concern during the upgrade
4. List any affected packages or components.
   - ds/node tuning operator
   - ds/node exporter
   - ds/machine-config-deamon
   - Any other component like OVS/sdn which