(RfC) Allow the product page to display external Knowledge-panel spec compliant data

[teolemon]

Why

• We have more and more external backends providing information that belongs on the product page (Nutri-Patrol, Open Prices, Folksonomy Engine)
• We have somewhat integrated Folksonomy Engine, but the integration leaves to be desired
• We have yet to integrate Nutri-Patrol and Open Prices

What

• Make Nutri-Patrol, Open Prices, Folksonomy Engine Knowledge-panel spec compliant
• Allow the product page to display external Knowledge-panel spec compliant data
• Display those external backends within the product page using JS

Beyond

• We could consider making Robotoff and Hunger Games compliant as well, as well as any new project we start
• The new use cases would provide a stronger incentive to evolve and complete the KP syntax, for the benefit of the web and the mobile app

cc @stephanegigandet @alexgarel @hangy @john-gom @Valimp @4nt0ineB @raphael0202 for comments

Related issues

Create a Knowledge Panel route for each product, so that we can integrate it in the ProductOpener Product Page openfoodfacts/open-prices#316
Integrate Nutri-Patrol in The Open Food Facts website openfoodfacts/nutripatrol#56
Create a Knowledge Panel compliant route for the Folksonomy Engine list of properties for a given barcode openfoodfacts/folksonomy_api#185

Part of

• 📖 Knowledge panels (Tracker) #5493

[teolemon]

Additional benefit, this could be the ground for making Knowledge Panel rendering a separate backend in Python