service to provide available rbacmanager implementations informations

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1447164 13f79535-47bb-0310-9956-ffa450edef68
service to provide available rbacmanager implementations informations

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1447165 13f79535-47bb-0310-9956-ffa450edef68
fix compilation

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1447167 13f79535-47bb-0310-9956-ffa450edef68