All Equipment Variants Overhaul

Clerical update for v1.14.* via Diff Merge. No notable difference found. Please let me know if you run into any issues.

• With tanks receiving the overhaul in NSB I'm expecting planes will eventually receive one as well. As such I do not plan on expanding or significantly modifying this mod, only to do minimal maintenance. The design goals of this mod has also changed; it is more accurate to call it Expanded Variants mod. With the NSB overhaul on tanks and improved vanilla Mechanized upgrades it's no longer relevant to try to overhaul everything.

Design Philosophy and Objectives: Toward the late game one is usually swimming in Land XP, or certain minor nations may be stuck with unusable Land XP due to their lack of access to higher technology or resources to produce advanced equipment. I wanted to give a reason to spend that XP but in a way that makes sense.

I also disliked vanilla variant upgrades are all positives; such that you'd ultimately just max out everything with no trade off. Therefore, many of the upgrade-able stats would impose significant trade offs, but it also gives you a reason to create branching variants. For example, you might have one variant of infantry weapons specializing in sniping gear for defensive bonuses (sacrificing hard attack), you might also have another variant that specializes in explosives for strong hard attacks, sacrificing soft attack and mobility.

Known issues: "Cuirass" upgrade is only relevant for the WW1 infantry weapons back when it was still used. I am unable to disable it for Infantry Weapon I, II, and III because of the way equipment tiers work. I'd like to still keep it and experiment it for a while before deciding whether or not to find other ways around the UI or drop it entirely.