Add GTIN to \CoreShop\Component\Product\Model\ProductInterface

[dkarlovi]

Q	A
Bug report?	no
Feature request?	yes
BC Break report?	no
RFC?	no

Having a GTIN for your products is very important in many ways, I'd argue it's more important than a SKU. GTINs are required (or at least heavily recommended) for many interoperability requirements (like adding JSON-LD rich result, for example).

GTIN ecompasses both EAN (Europe) and UPC (USA) so we can have one general field.

[dkarlovi]

Maybe it can have a more general name to cover ISBN or MPN also? 🤔