etcd

* 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