DISPATCH-56: Generate qdrouterd.conf man file from management schema.

Move documentation from qdrouterd.conf.5.in to the qdrouter.json schema, generate
the man file from the schema.

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1599320 13f79535-47bb-0310-9956-ffa450edef68