Allow day-2 soft RAID configuration of secondary disk (non-OS disk)

1. Proposed title of this feature request

Enabling day-2 configuration for software RAID for non-OS disk or data disk.

2. What is the nature and description of the request?
The doc [0] specifically mentioned about Raid Mirroring not supporting disk replacement and we have to reprovision the node.

[0] https://docs.openshift.com/container-platform/4.12/installing/install_config/installing-customizing.html#installation-special[%E2%80%A6]stalling-customizing

Can add additional drives for a data volume and apply raid configuration to them in day2, and not just when installing a new cluster (day-1)?

----> As per the documentation [1], this is currently not possible and possibly be considered for a feature request.

[1] https://github.com/openshift/machine-config-operator/blob/master/docs/FAQ.md#q-can-i-use-the-mco-to-re-partition-or-re-install

What is required:

Is to run mdadm commands on the host, a procedure that currently remains unsupported [1], at least for mirroring.

[1] https://docs.openshift.com/container-platform/4.12/installing/install_config/installing-customizing.html#installation-special-config-mirrored-disk_installing-customizing

Theoretically a software that reconciles MD configuration to a desired state upon disk insertion is possible and would be beneficial, but would not be suitable feature of MCO.

At this point in time, the asks for an RFE is to allow day2 soft RAID configuration. Also, that the manual repair of MD volumes, a supported action.
3. Why does the customer need this? (List the business requirements here)

Customer has new servers with nvme disks, and the hw controller only allows RAID for the OS drives. We need redundancy for the additional drives as well

4. List any affected packages or components.

Installer, MCO