Support a new qpid topology

There has been a bug open for a while pointing out that the way we
create direct exchanges with qpid results in leaking exchanges since
qpid doesn't support auto-deleting exchanges.  This was somewhat
mitigated by change to use a single reply queue.  This meant we created
far fewer direct exchanges, but the problem persists anyway.

A Qpid expert, William Henry, originally proposed a change to address
this issue.  Unfortunately, it wasn't backwards compatible with existing
installations.  This patch takes the same approach, but makes it
optional and off by default.  This will allow a migration period.

As a really nice side effect, the Qpid experts have told us that this
change will also allow us to use Qpid broker federation to provide HA.

DocImpact
Closes-bug: #1178375
Co-authored-by: William Henry <whenry@redhat.com>
Change-Id: I09b8317c0d8a298237beeb3105f2b90cb13933d8
Merge "Support a new qpid topology"