Infra-Ansible: Supported / Minimum Ansible Version

[tylerauerbeck]

I've seen a few PR's that have been opened that are making decisions and avoiding new modules based on trying to maintain functionality with older versions of Ansible. Is there a line in the sand that we want to draw that says we maintain compatibility with X number of versions?

I know eventually some CI will help us hash this out a bit better (and perhaps we could then even have tests/badges that indicate what versions of ansible a role is compatible with), but for now just thought it might be good for us to start the discussion.