Belt mechanics

This mechanic is intended to give a greater sense of growth and immersion, and also make some resources a bit more in demand, diversifying the loot of structures.
The starting number of quick access bar slots is decreasing. Belts of varying quality can be crafted or found.
The higher the "quality" of the belt, the more slots are added to the hotbar (more durable material will support more weight).
The belt needs a separate slot in the inventory (even knights wore belts with scabbards over armor, not instead).