- 🔪 'pure' ordered_categories.js and move logic to
  category_order_defaults (no need for two files for this stuff here)
- replace d3.bisector-based search-and-replace algo by lookup object,
  which bring number categories on par with their string rep
  (e.g. 1 same as '1' - see issue #1460)
- use native array sort() to order categories instead of d3 version