Export packaging components data in dedicated CSV export

[stephanegigandet]

Packagings data is now structured: different fields like shape and material for a varying number of components for products.
To ease the analysis of packaging data, we can generate a new CSV for packaging data, with 1 line per packaging component.

Note that only the child shape / material / recycling will be exported, so a PET bottle will have 1 line for a component with a PET material, and no line with the parent "plastics".

An alternative way to explore the data is to use the aggregated packaging stats per country and categories, which includes data on parents: https://world.openfoodfacts.org/data/categories_stats/categories_packagings_stats.packagings-with-weights.json