Assign additional items to order-groups when reconciling an order.

[torotil]

Sometimes our supplier delivers (very simlar) replacement products instead of the ordered one, because the ordered one is not deliverable at the moment. When reconciling the order, there is no way to assign the addditional items to one order group (marking the original product as undelivered works fine).

[wvengen]

Thanks for creating the issue. This has come up before in #222 and would certainly be useful.

[wvengen]

For more information, the current_orders plugin allows adding articles to group orders and adding ordergroups to articles. I have only tested it with the foodcoop-adam fork, but it may be a starting point. Ultimately, I'd like to merge this functionality into the main version of Foodsoft in this repository.