Enable SSL for groups.openstack.org

Enable the SSL connection for groups.openstack.org, required
by oauth2 authentication of openstackid.org.

New hiera variables:
- groups_site_ssl_cert_file_contents: x509 certificate of the vhost
in pem format.
- groups_site_ssl_key_file_contents: key of x509 cert in pem format.
- groups_site_ssl_chain_file_contents: parent certs of site certificate

Change-Id: Ia266e1ee057467e5149b84f8b5f8be98bf63180f
Implements: blueprint groups-oauth2-authentication
Merge "Enable SSL for groups.openstack.org"