API for dynamic plant spawning

[Niklp09]

Next step for https://github.com/mt-mods/plantlife_modpack/issues/27

• Clean up bushes mod (removal of global table, code order)
• Add simple api to attach a function to new spawned plants (works except the y pos is sometimes wrong)

The new decoration definitions for bushes are just dummys, this is a job for people who are familiar w/ noise params

[wsor4035]

sorry, i dont think adding an api mod here is the right way to do this. additionally it is recreating biome lib to a degree since biome lib was originally code extracted from this mod 🙃

[Niklp09]

I tried to recreate biome_lib in https://github.com/mt-mods/plantlife_modpack/pull/41 (and failed, lol). This mod has only one simple function to de-duplicate code that we need to remove biome_lib. I won't call this biome_lib 2.0.

Edit: this isn't an api rather a helper function

[wsor4035]

did some reading. this could be done much more performantly with schematic decorations and y slice probability to spice it up a bit

[Niklp09]

Doesn't seem to be needed.