GK mutation and K8s mutating admission policy

[ritazh]

What steps did you take and what happened: [A clear and concise description of what the bug is.]

Analyze the diff between GK mutation and https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/3962-mutating-admission-policies so we can give feedback to the KEP while the feature is in alpha since v1.30 and plan for what GK needs to do to provide consistency.

What did you expect to happen:

Anything else you would like to add: [Miscellaneous information that will assist in solving the issue.]

Environment:

• Gatekeeper version:
• Kubernetes version: (use kubectl version):

[ritazh]

GK mutation specific features:

• external
• expansion