* Define bare-metal `controllers` and `workers` as a complex type
list(object{name=string, mac=string, domain=string}) to allow
clusters with many machines to be defined more cleanly
* Remove `controller_names` list variable
* Remove `controller_macs` list variable
* Remove `controller_domains` list variable
* Remove `worker_names` list variable
* Remove `worker_macs` list variable
* Remove `worker_domains` list variable
* Review variables available in bare-metal kubernetes modules
for Container Linux and Fedora CoreOS
* Deprecate cluster_domain_suffix variable
* Remove deprecated container_linux_oem variable
* Drop `node-role.kubernetes.io/master` and
`node-role.kubernetes.io/node` node labels
* Kubelet (v1.16) now rejects the node labels used
in the kubectl get nodes ROLES output
* https://github.com/kubernetes/kubernetes/issues/75457
* Run a kube-apiserver, kube-scheduler, and kube-controller-manager
static pod on each controller node. Previously, kube-apiserver was
self-hosted as a DaemonSet across controllers and kube-scheduler
and kube-controller-manager were a Deployment (with 2 or
controller_count many replicas).
* Remove bootkube bootstrap and pivot to self-hosted
* Remove pod-checkpointer manifests (no longer needed)
* For Fedora CoreOS, only HTTPS downloads are available.
Any iPXE firmware must be compiled to support TLS fetching.
* For Container Linux, using public kernel/initramfs images
defaults to using HTTPS, but can be set to HTTP for iPXE
firmware that hasn't been custom compiled to support TLS
