[FORGE/FABRIC] Armor Curve

All hail the mixin!

• Armor degradation is a thing again! Not only that, the values are reflected onto the item in real time: as your armor takes damage, your armor bar will visually decrease to notify you of how much actual armor you have against an attack.
• Configs! The configs got a huge facelift: rather than picking between various reduction curves and the like, you can input a formula (with parsing provided by EvalEx) and it'll work off that. Available variables for "armor" and "toughness" are "armor", "damage", and "toughness"; for "enchantments", variables are "damage" and "enchant", and for degradation it's "remaining" and "max". Go wild.