Better sulfur caves

This datapack upgrade the sulfur caves biome with a new generation with:

New custom features:

- Giant sulfur spikes (like in dripstone caves) - Small sulfur pools - Sulfur gas on the ground

A new custom structure:

The sulfur labs, totally build with sulfur & cinnabar blocks.

It also changes the generation of sulfur spikes, so that it can now be generated in all vanilla underground structures. Moreover, sulfur pools and glow lichen are also more common for a more luminous cave.