Implement improved contribution flow in app

[teolemon]

Who for

End-users

What

Initial solution

• [] Webview based product addition and edition #509 (Dropped)

Individual native widgets

• Add the ability to add basic details if they are not available #903
• Nutrition input (Tracker) #511
  • We have a translated/ordered nutrient list available from the DART package
  • Initial implementation done by @monsieurtanuki
  • It needs to be added to Implement the new product addition flow #881 as well
• Implement Ingredients input #512
  • A PR has been started by @justinmc feat: Ingredients Page #707
  • It needs to be added to Implement the new product addition flow #881 as well
• Photo upload (tracker) #513
• Make the most use of the tag picker #1075
• Add support for edition of multilingual and/or free-text fields #522
• Implement Road to Scores for existing products #1325

Why

• As a user, I want to be able to get the scores on any product in the world, even if it's not in Open Food Facts
• As a developper, I want to implement the webview editing first to get a MVP asap (native is going to be long and complicated)

Part of

• Improve the app's core journeys to help the world to make better food choices #495