Added CC license for content of the site

Change-Id: I47388b8c411eb9bdc11329ef7039a2363de34dea
Fixes: bug #1161043
Reviewed-on: https://review.openstack.org/30801
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Evgeny Fadeev <evgeny.fadeev@gmail.com>
Reviewed-by: Evgeny Fadeev <evgeny.fadeev@gmail.com>
Tested-by: Jenkins