Use date of manufacturing instead of date of purchase to calculate expiry/best before dates.

[RoguedBear]

As from what I've used this app, when adding new products to inventory (purchasing products), the best before or the expiry date is calculated based on the date of purchase. For non-packaged food that makes sense, but If there could be a way which asks for the product's date of manufacturing and then calculate the expiry date based on the default expiry days value set in the product's master data, instead of the date of purchasing/adding the product to the inventory.

(PS: if some of my wordings seem like that stuff does not belong to Grocy webapp, that's because I mainly use the grocy android app while filling out inventory and adding products.)