What is missing?

Add dnsConfig parameter on PrometheusSpec and to AlertmanagerSpec to be able to custimize dns configuration on Prometheus and Alertmanager StatefulSets' pods.

Why do we need it?
Pod's DNS Config field enable users more control on the DNS settings for the pods.

Environment
All

• Prometheus Operator version:
  All

Anything else we need to know?:
If there are no objections on this proposal I ll raise a PR to implement this in the near future.