Easier support for RWX volumes for buckets.

[jortel]

Currently, the operator supports customization for RWX volumes for buckets primarily with the hub_bucket_volume_claim_name setting. This approach requires user to create both the PV and PVC by hand. I wonder if it would be a good improvement to add another variable hub_rwx_storage_class that can be blank by default but used to create the bucket PVC when specified. For example, to use NFS, the user can create a PV with a storage class of "nfs". Then, when installing tackle, the user creates the CR with:

hub_rwx_storage_class: nfs

and the operator does the rest. Just 1 less thing for the user to do.

[fbladilo]

@jortel , hub_bucket_volume_claim_storageclass can be set to "" when deploying with NFS storage (OCP defaults), in addition is flexible enough to be whatever the user desired storage class is for the hub bucket volume : i.e "fast" , "custom" , now, these storageclasses must exist and route properly in the cluster when requested.

Example empty "" for default NFS storage request below :

kind: Tackle
apiVersion: tackle.konveyor.io/v1alpha1
metadata:
  name: tackle
  namespace: konveyor-tackle
spec:
  hub_bucket_volume_claim_storageclass: ""