Allow for equipment "tagging"

[orenyk]

From DMCA:

Advanced gear not clearly marked in catalog, cannot tell what gear is advanced with checking the advanced gear book, which isn't always available

It seems as though the issue is that they have multiple ways of classifying equipment, such that a single tree is not sufficient. We could help with this by introducing a second, perhaps flat, classification of equipment (e.g. tags) that could be searched against.