QPID-4809: add support for setting configuration properties through the command line and BrokerOptions that can be used by the broker configuration store to resolve variables in the config, use this to supply the default port number values.

Povides chance to alter the ports when first starting the broker and using the initial config file to populate the config store.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1478696 13f79535-47bb-0310-9956-ffa450edef68