Commerce Item Discount UI

This module aims to provide a discount UI for Order Items. Currently, 2 discounts traits are available:
- amount-based discount
- percentage-based discount
Traits can be enabled on per order item type basis.

Use this module if the store administrator wants to adjust the order item price after the order was already placed, ex. due to lack of original packaging, missing instruction, wrong color, etc.
Please note that post-sale adjustments won't trigger order processors. In order to get the correct tax value, this module calculates the tax when the order item is saved.