Add support for backing up CSI backed PVCs

Purpose

kubernetes-sigs will soon be removing support for removing in-tree volume drivers, such as the commonly used (and supported by this repo) kubernetes.io/aws-ebs volume provisioners. The Velero package should offer support for what will become the new default storageclass provisioner, ebs.sci.aws.com, using the Velero CSI plugin.

Proposed Solution

IronBank has not yet hardened the Velero Plugin for CSI image, but a WIP MR could be made to update the templates and default values.yaml that would support the use of this plugin the the BB Velero deployment here and here (and probably a few other places) for when IB does eventually harden the image (a request has been made).