[EotE] Add Weapon mod rules

[Morgul]

Currently, EotE weapons are coded using Genesys mod rules; while we feel it's a much less broken system, that's not exactly up to us to decide for all users of the system. So, what we need to do, is to allow for users to "opt into" the Genesys rules for Eote, but we do need to code the painful original mod system. (Can you tell I'm thrilled about this? 😐 )

• Add EotE Mod system
• Add ability to opt-in to Genesys style mods