Allow DNS based access to GKE cluster control planes

[ukclivecox]

Checklist

• I did not find a related open enhancement request.
• I understand that enhancement requests filed in the GitHub repository are by default low priority.
• If this request is time-sensitive, I have submitted a corresponding issue with GCP support.

Describe the feature or resource

Allow DNS access setting for the ContainerCluster resource as per the anouncement

Additional information

No response

Importance

In my opinion this is high priority for easily allowing inter-VPC access to GKE clusters created via config connector.

[ukclivecox]

I assume this is the API needed?

https://github.com/googleapis/googleapis/blob/4fefaf151c721c138588efeba0e99591d51cbc16/google/container/v1/cluster_service.proto#L5865-L5876