Is your feature request related to a problem? Please describe.

We currently don't have a way of defaulting fields that is actually reflected on the API resources after admission.

This would be really helpful for users to understand what fields they have not specified and so have been defaulted.

Describe the solution you'd like

We can extend the current validating webhook to also contain a mutating webhook, and then define defaults similar to other Kubernetes packages.

Describe alternatives you've considered

Not persisting this information to the API and instead just considering defaults whilst processing resources.

/kind feature
/area api