Kubernetes the hard way on metal-stack

This is an adoption of Kelsey Hightowers famous guide "Kubernetes the hard way" for metal-stack.

Disclaimer: This is only a demo setup that is published for CKA preparation

Main differences to Kelsey's guide, which runs on GCP, are:

• LoadBalancing of the kube-apiserver can simply be done by setting the reserved static IP to the loopback interfaces of the controller nodes
• When using 10.244.0.0/16 for Pods, PodIPs are automatically distributed with BGP - so there is no route setup needed (11-pod-network-routes can be skipped completely)
• internal and external node ips have to be patched into the kubernetes node objects - this could be avoided with running the metal-ccm on the controllers (but it's good to do it once manually and see some grifts of kubelet: e.g. No way to configure addresses for a node with kubelet)