This interface can be used with an Offer implementation to indicate that an offer supports minimum required targets.
If set, the offer will not be applied unless the order contains at least the getMinimumRequired() number
of eligible targets.
For example, if this was set to 10 and an offer's target criteria was "item in category hot-sauces", then,
if the user added 9 hot-sauces to the cart, it would not apply.
If they added 10 or more, it would apply.
This is different than using the quantity on the OrderItemCriteria. If the OrderItemCriteria.quantity was
set to 10, the discount would be applied only for quantities in increments of
10 (so yes for 10, 20, etc. but not for 11, 12, etc.)