Add storyboard to gerrit

Created a new team, storyboard-core, intended to start off with ttx and
openstack-ci-core.

Change-Id: I256d13bcc0d5fbeedcefc2debeb832d483258d5b
Reviewed-on: https://review.openstack.org/37152
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Thierry Carrez <thierry@openstack.org>
Reviewed-by: Anita Kuno <anteaya@anteaya.info>
Reviewed-by: David Lenwell <dlenwell@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins