In order to improve the UX of kubeadm, it was decided to introduce the
following subcommands:

- `kubeadm config print` - this is currently only a placeholder for subcommands
  that deal printing of some kind of configuration.
- `kubeadm config print init-defaults` - prints the default combination of
  InitConfiguration and ClusterConfiguration. Selected component configs can be
  printed too if the `--component-configs` command line switch is used.
- `kubeadm config print join-defaults` - prints the default JoinConfiguration.
  This command also supports the use of `--component-configs`.
- `kubeadm config print-defaults` is deprecated in favor of
  `kubeadm config print init/join-defaults`.
Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>