feat: enable csi plugin for backups using nutanix csi and velero

[justicorn]

feat: #64 #57
Enabling the CSI plugin (should be moved upstream) to the init containers, as well as the default plugin for AWS.
This includes a patch version downgrade from upstream as the change to the Dockerfile did not create a required directory.
Upstream issues are being tracked on Iron Bank's plugin for csi and on the upstream Iron Bank Velero package. Once this is fixed, these changes can be removed.

[anthonywendt]

I would update the PR title to something like
feat: enable csi plugin for backups
This will be the title of the squashed PR and will be picked up by release please when merged to main.
There are workflows we can add to check for this when we improve our CI situation for this repo.

[blancharda]

The current changes look good!
Let's add a section (or expand the existing velero section) to include the steps used for testing.

I also think it makes sense to push this back up into core itself.. There's probably some discussion to have over enabling the CSI initContainer by default, but I think it's worth including the images at the very least and maybe exposing it as a configurable option.

I expect that discussion/PR/release to take a bit more time, so I say we merge this (after the docs) and then roll it back when we have an appropriate upstream resolution.

[blancharda]

Looks good!

I added a note regarding RWX limitations.

[blancharda]

flava