Documents and makes repeatable the Admin API writes for Fase 5 Etapa 2
sub-fase 1: assign real Medusa collections (Toy Story, Intensamente,
Lilo & Stitch, Universo Marvel, Reino de Frozen) to 9 legacy products,
and the missing "Figuras de accion" category to cybertron-sentinel.
Categories for the 17 legacy products were already correct and are
untouched.
