ACQ+Vandelay detect existing queue with same name

ACQ+Vandelay detect existing queue with same name

Within the acq/vandelay agent, detect when a user has entered the name
of one of their existing queues.  When detected, update the queue
selector to match the found queue (which updates the linked match set
and clears the queue selector input).  Otherwise, users may not realize
they are adding items to an existing queue (with a pre-linked match
set).

Signed-off-by: Bill Erickson <berick@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>