[nutrition] Allow to add nutriments

[alexfauquette]

Should be able to add extra nutriments compared to the detected one. In this target we can list:

• Have a list of all nutrients ids with:

  • their display order
  • are they shown by default (the one in EU nutri table)
  • their default unit
  • are they a sub nutrients to add a bit of left padding (for example sugar is a sub element of carbohydrate, same with saturated-fat and fat)

• if product already have a nutriment set that is not detected show it

[raphael0202]

Extra bonus point if we have the USDA order for USDA tables, but we should first detect USDA tables!