Publish Kubernetes version compatibility matrix

[jackfrancis]

Due to the various dependencies upon the Kubernetes API and Kubernetes resource type system (the way we expect to be able to introspect resource objects after retrieving them from the k8s API), we should thorougly test all functionality against all Kubernetes versions, and identify if any API breaking changes introduce breakages in kamino functionality.

[Michael-Sinz]

Over all, the matrix from kubernetes standpoint should be rather wide (all?) versions but the VM/OS configuration issues may be more subtle. That is, the way aks-engine lays down configuration and startup code and how much "node name branding" is done and how it is done will matter more.