[lua] Refactor PDIF clamping and simplify code

[WinterSolstice8]

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What does this pull request do?

After talking to Jimmayus and other math nerds in the math nerds group chat..

adjusts ranged pdif to be half of melee pdif

Corrects pdif caps for corrected areas/non corrected areas for mobs via a note in https://forum.square-enix.com/ffxi/threads/31310-March-27-2013-(JST)-Version-Update

mobs in a corrected zone should be able to reach 3.0 pdif after crit and then another 1.0 pdif from correction

cratio cap: 2
pre randomizer cap: 4

but when in a non-corrected zone, the caps are the same.
Refactors usage of caps (there was some clamps that were not necessary based off of player optimizations on the wiki and not reality)

Closes phoenixffxi#38

Steps to test these changes

get meleed by stuff

[Xaver-DaRed]

Looks sane