Split deploy steps in separate playbooks: part1 (#3451)

* Fix bootstrap_os/ubuntu idempotency

* Update bastion role

* move container_engine in sub-roles

* requires ansible 2.5

* ubuntu18 as first CI job

roles/container-engine/docker/handlers/main.yml

@@ -0,0 +1,35 @@
+---
+- name: restart docker
+  command: /bin/true
+  notify:
+    - Docker | reload systemd
+    - Docker | reload docker.socket
+    - Docker | reload docker
+    - Docker | pause while Docker restarts
+    - Docker | wait for docker
+
+- name: Docker | reload systemd
+  shell: systemctl daemon-reload
+
+- name: Docker | reload docker.socket
+  service:
+    name: docker.socket
+    state: restarted
+  when: ansible_os_family in ['CoreOS', 'Container Linux by CoreOS']
+
+- name: Docker | reload docker
+  service:
+    name: docker
+    state: restarted
+
+- name: Docker | pause while Docker restarts
+  pause:
+    seconds: 10
+    prompt: "Waiting for docker restart"
+
+- name: Docker | wait for docker
+  command: "{{ docker_bin_dir }}/docker images"
+  register: docker_ready
+  retries: 10
+  delay: 5
+  until: docker_ready.rc == 0