CSI Drivers as Add Ons

### Description

Provide CSI drivers as add-ons that can be used to alter mount properties for application containers.

### Possible solution

I have a need to use a CSI driver with my single container app. Specifically, https://github.com/awslabs/mountpoint-s3-csi-driver. Unfortunately, I do not control development of the container I need to provide mounts to.

Would it be too much trouble to have a few CSI drivers available as add-ons. How much additional plumbing would be needed in Kubero to make them available to containers as mount options?

### Alternatives

_No response_

### Additional information

_No response_

Review Kubero's add-on and container mount configuration entry points, then compare them with the mountpoint-s3-csi-driver requirements linked in the issue. Define the required plumbing and configuration boundaries; done would mean a concrete, agreed design for exposing selected CSI drivers and mount options to application containers.

Written by the indexing model from the issue text.