[Suggestion] Add height-spread projection for placed feature generator

[MrNovado]

Related to #196

Currently it is hard to understand how height-range and other height related modifiers affect feature placement. Would be nice to switch visualizer to show x y projection.

Thanks,

PS. is there any example of how to properly limit height_range of a feature, like minecraft:large_basalt_columns for example, so that it wouldn't be placed above certain Y coordinate?