Purpose: Some institutions do not allow acquisitions librarians to create purchase orders for multiple items.

Requirements:

1. Add "Purchase Order" to settings for the orders module

2. Add setting for "Maximum number of purchase order lines per purchase order"

3. The default should be 999 (This corresponds to the max number of digits that can display in purchase order line number eg. PO#-###)

4. This limit can not be less than 1 and must be a whole number