This is first version of the command. It prints IPs of master and cluster
services. Should be improved once generalized labels are implemented #341.
It requires label kubernet.io/cluster-service=true set for cluster services.
Follow up cl after discussion in #4417.
generate man pages for kubectl using the cobra.Command information.
This will directly create files in (by default) docs/man/man1/ called
kubectl*.1. Each child verb/cobra command will gets its own man page.
