Soil Forming Factor linkages

[brownag]

@dylanbeaudette

Following on the ideas posted in /misc in 8771db5

Can this idea be extended to include more comprehensive lists of features and multiple sources of the assignment of what is related to what?

I think we need to devise a plan for versioning this type of stuff, and figuring out what the source is.

e.g. Can we assign similar SFF linkages for all feature names from https://github.com/ncss-tech/SoilKnowledgeBase/blob/main/inst/extdata/KST/2014_KST_EN_featurelist.json? If we were to do that, how would we document what was from Bockheim and what was added after or changed?