Introduce per provider feature gates for Azure/GCP CCM promotion

Background

We tried to promote Azure CCM to GA, but it unfortunately left us with disruption and had to be reverted. 

To be able to promote the feature to GA in the future, we need to introduce a single source of truth for feature promotion, see https://github.com/openshift/enhancements/pull/1373 for design.

Once this has been implemented, promoting the feature should be a case of a single PR, which in turn, would mean we can run payload acceptance tests against the PR to prove the reliability of the feature.

For CCMs, this means having separate feature gates for promoting both Azure and GCP CCMs to GA, so that they can be promoted individually when ready.

This is required now that we have identified the CCM as the source of the issue for https://issues.redhat.com/browse/OCPBUGS-11308

Steps

• Introduce new feature gates for Azure and GCP CCMs
• Update all related providers to observe both new and old feature gates
• Migrate observers to rely on feature gate calculated status rather than vendored code

Stakeholders

• Cluster Infra
• TRT

Definition of Done

• Have the ability to promote the CCMs to GA in a single PR

• Docs

• Will want to document the new feature gates

• Testing

• N/A