Quick getting started guide for kops.
Also try to provide some guidance as to when to use kops and when
kubeadm; based on discussions with sig-cluster-lifecycle that kubeadm is
a building block and not a provisioning tool.
I used "kubeadm" as a simplifying concept for "kubeadm and the other
work done by sig-cluster-lifecycle that kubeadm is a part of", in that
tools that don't (yet) use kubeadm are still leveraging the kubeadm
stream of work.