Remove Makhleb corpse sacrifices

Since I failed to say this when I remove Okawaru sacrifices, I'll
describe here why corpse sacrifices are being targeted:

In general, corpse sacrifices have a huge interface burden. Players need
to go over every single corpse generated in the game they do not a
specific use for and press “p”. This is so bad there is an automation
option - a clear sign that a system isn’t producing enough decisions.

This would be possibly acceptable if there was a massive benefit to
keeping corpse sacrifices, but in this case there isn’t. For most
characters, there are some corpse which should obviously be sacrificed
(those the character can’t eat or animate), some amount of corpses which
clearly need to be eaten/butchered for hides, and a very tiny amount of
corpses which make the player seriously consider the cost/benefit
analysis of eating the corpse versus sacrificing it to their god.

Corpse sacrifices do cause some minor distinction between species which
need to eat different amounts of corpses, but this is an extremely small
benefit when compared to the massive downsides of corpse sacrifices. (In
addition there are other ways species interact different with the gods,
most notably different Invocations aptitudes).
Increase Makhleb piety to compensate for no corpse sacrifices

Specifically, increase it for MH_NATURAL monsters (which is highly
correlated with dropping a corpse). The piety for those monsters is 4/3
what it used to be.

This is an estimate, anybody else should feel free to tweak this if they
feel Makhleb piety is off.
Adjust Makhleb's ^ screen for piety changes