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

roles/bootstrap-os/tasks/bootstrap-fedora.yml

@@ -17,6 +17,7 @@
     value: "{{ http_proxy | default(omit) }}"
     state: "{{ http_proxy | default(False) | ternary('present', 'absent') }}"
     no_extra_spaces: true
+    mode: 0644
   become: true
   when: not skip_http_proxy_on_os_packages