Fix etcd install with docker and etcd_kubeadm_enabled (#5777)

- This solves issue #5721 & #5713 (dupes)
  - Provide a cleaner default usage pattern for the download role
    around etcd that supports 'host' and 'docker' properly
  - Extract the 'etcdctl' as a separate task install piece and reuse it where
    appropriate
  - Update the kubeadm-etcd task to reflect the above change

roles/kubernetes/preinstall/tasks/0040-set_facts.yml

@@ -185,7 +185,6 @@
     kube_etcd_cacert_file: "etcd/ca.crt"
     kube_etcd_cert_file: "apiserver-etcd-client.crt"
     kube_etcd_key_file: "apiserver-etcd-client.key"
-    etcd_deployment_type: host
   when:
     - etcd_kubeadm_enabled