Add an embargo-notice@lists.openstack.org mailing list for private
advance notification of embargoed security vulnerabilities to
downstream stakeholders. Subscribers will be manually added by the
OpenStack Vulnerability Management Team, and all posts to this list
from non-VMT members will be moderated by the VMT. This is intended
as a very low-volume ML for announcements only, and followup replies
will be directed to use comments in corresponding private bugs
instead of the embargo-notice list.
Change-Id: I9a31fd5151e45644c9fb2209b69250b108b04889