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/tasks/pre-upgrade.yml

@@ -0,0 +1,32 @@
+---
+- name: Ensure old versions of Docker are not installed. | Debian
+  package:
+    name: '{{ item }}'
+    state: absent
+  with_items:
+    - docker
+    - docker-engine
+    - docker.io
+  when:
+    - ansible_os_family == 'Debian'
+    - (docker_versioned_pkg[docker_version | string] | search('docker-ce'))
+
+- name: Ensure old versions of Docker are not installed. | RedHat
+  package:
+    name: '{{ item }}'
+    state: absent
+  with_items:
+    - docker
+    - docker-common
+    - docker-engine
+    - docker-selinux
+    - docker-client
+    - docker-client-latest
+    - docker-latest
+    - docker-latest-logrotate
+    - docker-logrotate
+    - docker-engine-selinux
+  when:
+    - ansible_os_family == 'RedHat'
+    - (docker_versioned_pkg[docker_version | string] | search('docker-ce'))
+    - not is_atomic