* Update Terraform examples to use Terraform v0.13
* Refresh examples to show Fedora CoreOS and Flatcar Linux
* Remove the etcd3 example, not worth it to maintain
* Refactor examples to boot provision minimal hosts
with Fedora CoreOS or Flatcar Linux
* Remove the etcd3 cluster example or other specific
kinds of hosts
* Update script get-fedora-coreos
* Remove script get-coreos