Improve barcode scanning

[lebaaar]

Add more ways to get product details from product. Currently just food API is used. Users should be able to scan any barcode, of any item and it should find it. Add more APIs that return details, if first fails, go to second one, then third... until product details are found

Currently, if one scans barcode of non food item it sometimes results in Unknown product:

[lebaaar]

Added barcode_service.dart where the following APIs are used:

• https://tr-en.openfoodfacts.org/discover
• https://upcitemdb.com/
• https://www.gtinsearch.org/

Most good options are paid. These include:

• https://www.barcodelookup.com/
• https://go-upc.com/
• https://gtinhub.com/

If app gets popular enough, we can purchase a more expensive API for barcode scanning.
Leaving this issue open, added vX label.