OAK-90 : Implement Principal Management (WIP)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1430943 13f79535-47bb-0310-9956-ffa450edef68
 OAK-91 - Implement Authentication Support (WIP)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1430947 13f79535-47bb-0310-9956-ffa450edef68