weight and volume rebalance of welding rig and kitchen buddy

I originally took the weight and volume of these items from the kitchen
unit.  After comparing some of the values on these to what the totals
for the parts themselves are, I've come to the conclusion the values on
the kitchen unit are completely insane.  Rebalancing the stuff I made to
more reflect reality, and may adjust kitchen unit in a seperate PR.
kitchen buddy recipe and weldrig crafting skill adjustment