Update how modifiers are updated in db

[bogadisa]

Very outdated method, currently there is very little connection between what is already available and what is new. To change this, I propose a version control system. Instead of editing the original modifier file, a new version is created which contains information on how each modifier changed (nullable).

This became an issue because of a wording change of Watcher's eye mods related to reflect immunity:
#% reduced Reflected Elemental Damage taken while affected by Purity of Elements $\rightarrow$ #% of Elemental Damage from your Hits cannot be Reflected while affected by Purity of Elements