Annotate for External DNS hosted CP components for `Private` clusters

When a HostedCluster is configured as `Private`, annotate the necessary hosted CP components (API and OAuth) so that External DNS can still create public DNS records (pointing to private IP resources).

The External DNS record should be pointing to the resource for the PrivateLink VPC Endpoint. "We need to specify the IP of the A record. We can do that with a cluster IP service."

Context: https://redhat-internal.slack.com/archives/C01C8502FMM/p1675432805760719