KNL-298 Support Authentication ID.

This adds support for an Authentication ID which users can be searched on from outside the kernel and also supports using an authentication ID when container based authentication is being used.

git-svn-id: https://source.sakaiproject.org/svn/sakai-mock/trunk@306641 66ffb92e-73f9-0310-93c1-f5514f145a0a