Refactor stock item lookup a bit
Refactor stock item lookup a bit

- add stock_item_for
- use to_h instead of each_with_object
- remove the order(:id) since we have db-level uniqueness now

Arpsara/solidus,jordan-brough/solidus,Arpsara/solidus,forkata/solidus,Arpsara/solidus,forkata/solidus,pervino/solidus,pervino/solidus,jordan-brough/solidus,forkata/solidus,pervino/solidus,forkata/solidus,jordan-brough/solidus,pervino/solidus,Arpsara/solidus,jordan-brough/solidus