Revamped mineshafts

Mineshafts right now are looking a little bland especially when compared to newer things like the Ancient city, and they don't seem to have been updated in like 10 years.

Some ideas to make them better include: Dead ends being collapsed instead of abruptly ending, New rooms/spawners, Surface entrances, Traps, A more modern look with all the new blocks and items, Better loot while also maybe being harder to traverse.