Decouple materials and ingredients ids from processes ids

[vjousse]

🔧 Problem

The id fields used in materials.json and in ingredients.json are the same than the corresponding processes.json entries and are used to make the link between the files. It implies than 2 different ingredients can’t be linked to the same process id.

🍰 Solution

Keep the same value for the id on the ingredients.json and materials.json files to avoid breaking the public API. Re-generate the ids of the processes.json files and add a processId field to ingredients.json and to materials.json that will reference the newly generated ids.

🚨 Points to watch/comments

Some process ids are used by the public food API (for cooking), so it will require a breaking change in the API versioning.

🏝️ How to test

TODO