Adding the old scrapped sewers to the spawn rework

The sewers were around spawn very early in the servers history, but the vast majority of it was made inaccessible and later removed. I’ve often seen it requested to be brought back to our current spawn, so I think a redesigned one could be a neat addition to the new spawn!

With the recent addition of the tuff variants+all the new stone pillars, there is good opportunity to make them much more detailed, too.

It’d be a nice callback for those who have stuck around with the server for a long time, and also provide spots for curious players to explore. Could even be a good spot to hide future secrets!