PowerMax config options have changed since newton.
Updating them to the latest. Supports both iSCSI and FC
drivers.
Supports deploying multiple instances of the
cinder::backend::dellemc_powermax backend
(e.g. one iscsi + one fc, multiple iscsi, etc.).
Depends-On: https://review.opendev.org/#/c/708960/
Change-Id: I25be51121390afd7ed3d0f0249733d3ccaf557de