Add back Nether Galleries

[Hugman76]

What is your idea about?

Based on the biomes removed in the v3.0.0 update

Content

• [ ] Give the configured features for the huge mushrooms new unique shapes The new features could also use the minecraft:tree type (this requires some investigation beforehands)
• [ ] Thick Mushroom Stems Thick mushroom stems would act as the "log" block of the new mushrooms. They would come in 3 variants for each color blindness type, and resembe the regular mushroom stem with pale color smudges over it
• [ ] Remove all the old mushrooms and mushroom blocks (they are not used anywhere)
• [ ] Add back new mushroom blocks for each visible color type of color blindess (eg. Achromatopsian Grey Mushroom)

Datafixing all of these changes might be tedious, so we might want to push these alongside the potential removal of other features (taller nether forests?) to mark the version as a breaking one.