Unindex recipes and materials

Not having an index in json files makes it easier for users to index by what they need. That means the data doesn't have to change if one index or an other becomes more pratical (id vs id:metadata vs name ,... ). It also makes it possible to consider one element as a document of a database.

All json files are now unindexed except for recipes and materials.

I think materials could have a format like this :

{
  "material":"rock",
  "multipliers":  {
    "257": 6,
    "270": 2,
    "274": 4,
    "278": 8,
    "285": 12
  }
}

I'm not sure whether multipliers should be unindexed too since it only has one value, maybe.

The recipes file is currently indexed by output id. The simplest solution might be to just remove that indexing, and to say that the recipes should be ordered by a lexicographic order on (id,metadata) in order to have a decent diff.

Compare the recipes and materials JSON files with the other already-unindexed data files, then trace consumers that rely on their current indexing. Resolve the open question about indexing multipliers and define the recipe ordering before removing the remaining indexes; done means both datasets follow the agreed format and consumers still load them correctly.