Add 'user' attribute to queue in XML/JMX

Currently a queue is tagged with the user who created it, if it is created over the wire.
This leaves out keeping audit of the user who may have created if declared in broker.xml, as such should be possible to tag a queue with a user that would be associated with creation.
Also whilst this is exposed over the bespoke views for the console (new panels), the attribute isn't exposed over JMX and is useful to capture.

This JIRA is to implement both the ability to add a user tag to broker.xml to associate the creator user, and like wise simply expose the extra attribute in QueueControl JMX.