Add cyborg's API doc link to the OpenStack API landing page
Add cyborg's API doc link to the OpenStack API landing page

This patch adds cyborg's api-ref link to OpenStack API landing Page:
https://developer.openstack.org/api-guide/quick-start/

Change-Id: I43f019aa62bf2d8bcde6ae1caccc0bcf0f5da212

openstack/api-site,openstack/api-site,openstack/api-site,openstack/api-site