Fixes reagents extra consumption + some cleanup

Fixes  #4608

* Also removed the inexistent reagent/plasma subtype of hellwater (i kept hellwater for now, as someone may find a use for it, but there absolutely no way get the reagent in someone...)

* Purifying someone with unholy water in it's body (i.e the chaplain hitting him with the bible) now turns the unholy water to holy water instead of space cleaner (sorry for your joke, whoever did it)

* Unholy water is still a _fuel_ subtype so that it can be lit if somehow extracted from someone