Allow to display barcodes when listing products

[CharlesNepote]

Allow to display all barcodes when listing products.

We could accept "shift+b" keyboard shortcut when listing products.

[svensven]

does this mean show just the numbers, or a graphical barcode?

[CharlesNepote]

A graphical barcode. The barcode library is already loaded by default, see @require https://cdn.jsdelivr.net/jsbarcode/3.6.0/JsBarcode.all.min.js.

Use cases:

• test Open Food Facts apps with many products
• control if an app is using Open Food Facts or not
• make a demo of Open Food Facts apps (or other apps)
• etc.