First pass at organizing our docs for three separate audiences:
User, Cluster Admin, and developer. Wrote a top-level guide
for each one, by selecting parts of the old docs/README.md.
The new docs/README.md mostly points to these 3 guides.
The User's guide is for anyone who wants to run programs and services on an exisiting Kubernetes cluster.
The Cluster Admin's guide is for anyone setting up a Kubernetes cluster or administering it.
The Developer guide is for anyone wanting to write programs that access the kubernetes API,
write plugins or extensions, or modify the core code of kubernetes.