Add cluster feature gate for Shared Resource CSI Driver

User Story

As a cluster admin
I want to enable the shared resource CSI driver via a feature gate
So that I can enable the CSI driver on a tech preview basis

Acceptance Criteria

• The feature gate for the shared resource CSI driver (CSIDriverSharedResource) can be turned on by using the TechPreviewNoUpgrade feature set.
• Feature gate name is accepted to the list of tech preview features.

Docs Impact

No direct impact - docs related to this will be addressed in BUILD-284

Notes

Feature gates are enabled at the cluster level through the FeatureGate API object.
Feature gates and their associated feature sets are declared in openshift/api here: https://github.com/openshift/api/blob/master/config/v1/types_feature.go#L107-L132.
TechPreviewNoUpgrade is a pre-defined feature set that turns on all tech preview features in the cluster. Adding a feature gate to a feature set requires API review.
Once a feature gate is added to a feature set, library-go needs a vendor bump of openshift/api to pick up the new feature gate -> feature set mapping.