Refactored "Nutrient items" into Reagents

Old "nutrient" items were in my opinion a bit snowflakey and didn't work
well with the new irrigation changes. Now you can dump a bunch of
nutriment into a bucket. Also did not want to create new types of
reagents for L4D and Robust Harvest so I used existing chemicals that
had the same described effects.
Weed/pest Killers actual Reagents + tweaked L4D

Filled all the nutriment bottles with nutriment + what ever else they
had.

Changed the mutagen to radium in "soft mutate" amounts of 3 (hopefully
any damage it does it covered by the 28 nutrients).

Added new "weedkiller" and "pestkiller" chemicals with recipes using
half of diethylamine + toxins respectively.
Removes unused vars
More Tweaks + Remove YieldMod and Mutmod on trays
reagent/plantbgone/weedkiller > reagent/weedkiller
Thank god for shift+tab and select all

Gave full paths to Chemistry-Reagents and Chemistry-Recipes