QPID-4390, QPID-4743: configuration improvements from review

- Rename the embedded initial config file to initial-config.json
- Ensure the default vhost store path is unique by including its type and vhost name.
- Rename ports to remove the port number.
- Remove leftover systests config.xml file.
- Stop shipping unused virtualhosts.xml in example config to reduce confusion

merged from trunk r1467938


git-svn-id: https://svn.apache.org/repos/asf/qpid/branches/0.22@1469904 13f79535-47bb-0310-9956-ffa450edef68