Copy promo codes across shops#773

It would be great to introduce a Copy feature of promo codes across locations. I imagine this being part of the existing Menu Copy functionality in the reseller panel, to ensure consistency witt products in menus.

Additionally, creation, edition and delition of promo codes via API would be ideal.

This is critical for groups with multiple locations, where manually adding codes in each shop is a recipe for errors and inconsistencies… and just not operational when you have tens of shops.