Doomlike Dungeons

• Added away to append mobs (and even blocks) to themes without overwriting them, so data packs based on several other mods can be used at once

• The Lordranian Crystal Sword is now based on a golden sword instead of a stone sword (more fitting ot the concept).

• Added a config option that allows "degenerate" building (merging with caves and other empty spaces) to be turned off without using a data pack to change all the themes

(This will most likely be the version that gets ported to 1.21, when I'm ready, but will probably not be back ported because I need a break.)