QPID-5138: Introduce preferences provider interface and its implementation storing preferences on file system

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1523217 13f79535-47bb-0310-9956-ffa450edef68
QPID-5138: Integrate preferences provider into Broker model, create association between preferences provider and authentication provider, add preferences provider recoverer and factory

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1523218 13f79535-47bb-0310-9956-ffa450edef68