Move to Ansible 3.4.0 (#7672)

* Ansible: move to Ansible 3.4.0 which uses ansible-base 2.10.10

* Docs: add a note about ansible upgrade post 2.9.x

* CI: ensure ansible is removed before ansible 3.x is installed to avoid pip failures

* Ansible: use newer ansible-lint

* Fix ansible-lint 5.0.11 found issues

* syntax issues
* risky-file-permissions
* var-naming
* role-name
* molecule tests

* Mitogen: use 0.3.0rc1 which adds support for ansible 2.10+

* Pin ansible-base to 2.10.11 to get package fix on RHEL8

tests/cloud_playbooks/create-do.yml

@@ -79,7 +79,7 @@
       register: droplets
       with_items: "{{ instance_names }}"
 
-    - debug:
+    - debug:  # noqa unnamed-task
         msg: "{{ droplets }}, {{ inventory_path }}"
       when: state == 'present'
 
@@ -87,4 +87,5 @@
       template:
         src: ../templates/inventory-do.j2  # noqa 404 CI templates are not in role_path
         dest: "{{ inventory_path }}"
+        mode: 0644
       when: state == 'present'