[no squash] Disable jungletree generation when default isn't available

[Niklp09]

Resolves #42 and maybe #12.

• Remove unused params from biome_defs (I kept biomes due to https://github.com/mt-mods/moretrees/blob/3e424b2797723640a4c915da664f30fbd9e80934/init.lua#L141)
• Disable jungletree generation when default isn't available

Might make sense to generate jungletrees when the game provides somethink like xcompat.materials.jungletree (not implemented in xcompat yet). Then we could nuke the copied node completely and alias it when default is loaded.