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/vars/fedora.yml

@@ -0,0 +1,20 @@
+---
+docker_kernel_min_version: '0'
+
+# https://docs.docker.com/install/linux/docker-ce/fedora/
+
+docker_versioned_pkg:
+  'latest': docker-ce
+  '18.03': docker-ce-18.03.1.ce-3.fc28
+  '18.06': docker-ce-18.06.1.ce-3.fc28
+
+#
+# This is due to the fact that the docker
+# packages available on Fedora are too recent
+#
+docker_version: "latest"
+
+docker_package_info:
+  pkg_mgr: dnf
+  pkgs:
+    - name: "{{ docker_versioned_pkg[docker_version | string] }}"