Give the option to set temporary product info when barcode does not exist on OFF

[odin-h]

Problem

When adding the price of a product that does not exist on open food facts, the only identifying feature for that price entry is the barcode.

Proposed solution

Let the user manually enter the weight, product name, etc.. and use that info temporarily until someone adds that product to open food facts.

[raphodn]

linked with #323 & #459