Implement Ingredients input

[teolemon]

Who for

• Users who care about ingredients (Vegan, Allergies, Additives, Food processing…)

What

• Design doc
• Ingredient input, augmented by OCR, and easy to correct (possibly by highlighting and tokenizing unrecognized ingredients)
• Allow to extract and save ingredients #107

Why

• We don't have all the ingredient lists in many countries, including France as well as countries with a limited amount of products

Part of

• Implement improved contribution flow in app #505

Blocking

• Ingredients analysis completion pipeline #520
• Implement full/guided ingredients origins input (tracker) #517

Old mockup

[justinmc]

Played around a little bit with this today following these mocks. I have a bunch of questions but I'll open a WIP PR and ask them on there once the code is more complete.