This patch also changes CONTRIBUTING.rst file in root directory
of the repo to fit with new cookiecutter template proposed in
the community goal description.
* Update the URLs affected by the doc-migration
(/developer/<project>/ to <project>/latest/)
* Follow content rearrangement
* Convert links to local documents into :doc: or :ref:
* Use https instead of http for the updated links on docs.openstack.org.
Part of the doc-migration work.