Add boulder field prop generator

[BlackYps]

Adds the changes to the HIGH_RECLAIM generator from #384 as a new prop generator.

It has rather high reclaim, but not as high as the HIGH_RECLAIM generator. We could add this as a second prop generator to the HIGH_RECLAIM map style or leave leave that style as is.

[Sheikah45]

We can add it as an option to the High reclaim style