AWS support draft

This is a very early version of code that adds possibility to bring up a Kubernetes cluster on AWS. It implements a "happy path" scenario at the moment.
I thought I'd ask for some comments and if this work is needed at all before proceeding with making this code ready for merge.
I wonder if this should set `KUBERNETES_PROVIDER` to `aws` for convenience, fails if you run it without setting it explicitly otherwise. This script is AWS specific anyway.