Amerisync - Add option to sync handling charge

In Amerisync, under special items, add Handling Item and allow a mapping to an item in Quickbooks. This would behave just like the current "Shipping Item," but for handling charges.

This is needed in addition to the "non-mapped item." Currently if we were to map "non-mapped item"  to a "handling" item in quickbooks, the imported order would be wrong some of the time. This is due to the fact that some orders include phantom items and those would erroneously be mapped to handling charge.

So we just need another special item in Amerisync that behaves exactly like Shipping Item, but instead it is Handling Item.

Thank you