Adding a tool for generating requirements.yml
files for each Openstack-Ansible role. This
tool is intended to be used by maintainers of
OpenStack-Ansible. The goal of the generated
requirements.yml files to allow end users the
ability to consume roles without needing to
use all of OpenStack-Ansible.
Change-Id: I8f4c0bf3ea4366bd84b671f796cedc07e5d4db80