Add support for "Fleshrender" unique (and general poison stacking mechanics)

[majochem]

Description of the problem being solved:

Adds support for mods from the new 3.28 unique "Fleshrender"

• Cannot Poison Enemies with at least 12 Poisons on them
• Inflict 3 additional Poisons on the same Target when you inflict Poisons with this weapon
• Wither on Hit with this weapon against Enemies with at least 12 Poisons on them

Additional changes

• DoublePoisonChance was renamed to AdditionalPoisonChance because it's not technically "double"
• Breakdown for Poison Stacks was improved
  • now shows mods that modify additional poison stacks or poison stack limit
  • also shows active poison stack limit and theoretical uncapped poison stacks
• Added new "MIN" modType and corresponding ModStoreClass:Min() function as counterpart to "MAX" and ModStoreClass:Max()
• Also added explanation for "MAX" and "MIN" to modSyntax.md documenation
• Added PoisonStackLimit of 1 to Viper Strike of the Mamba via SkillStatMap

Steps taken to verify a working solution:

• Item mods get parsed correctly
  • Multiple poison stacks only work for weapon
  • Poison stack limit from weapon is global
  • Equipping weapon enables Withered via config
• Poison stack limit applies correctly in calcs
  • Only has effect if stack limit can be reached
  • AdditionalPoisonStacks correctly interacts with AdditionalPoisonChance (can get e.g. 4.33 poison stacks)
  • Only lowest poison stack limit applies
  • "exceeding" cap is possible if limit % poison stack per hit != 0 (e.g. if limit is 2 and you apply 4 poisons with each hit, the effective limit is 4
• CannotMultiplePoison prevents additional poison stacks

Limitations:

• This only contains only the parsing/calculation for the mods. It does not add the actual unique item to the database (as I believe that's handled by a different PR)
• The "Condition:SinglePoison" flag logic still needs to be reworked (it technically already didn't work correctly with additional poison stacks from "Betrayal's Sting"), but I'll do that in a separate PR
• Viper Strike of the Mamba will need to be assigned "CannotMultiplePoison" via SkillStatMap.lua once 3.28 gem data is available
• There are currently still edge cases they don't show correct DPS when taking maximum poison stacks into account
  • Using Count and Full DPS (e.g. for Totem Builds), will not limit total poison stacks correctly and therefore inflate DPS (this has also already been the case for Viper Strike of the Mamba)
  • Multi-hit damage skills with varying damage ranges (e.g. Lancing Steel of Spraying, Blade Flurry) will lead to wrong or at least statistically unlikely average base damage for poisons, because they take the average of all hits, rather than the first x hits

Link to a build that showcases this PR:

Fleshrender Test Build

After screenshot:

Item with parsed mods

Poison Stack Breakdown