Bug 9987: Remove DB field aqorders.biblioitemnunmber

The DB field aqorders.biblioitemnumber seems to be unused except to get
the itype on the spent.pl page.

This information can be retrieved uising another SQL join.

Test plan:
Try a complete workflow in the acquisition module: create an order,
receive it, play with the syspref AcqCreateItem.
Check that no regression is found and that the data for existing
orders don't change.

Signed-off-by: Mathieu Saby <mathieu.saby@univ-rennes2.fr>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>