[terraform-ibm-base-ocp-vpc] Updates required to handle `ibm-storage-operator`

[ocofaigh]

Looks like by default in OCP 4.15, the ibm-storage-operator addon is installed. We need to add code to handle this (same way we did for vpc-block-csi-driver.
Take same approach as terraform-ibm-landing-zone (being tracked internally here)

[Aashiq-J]

#483