A round of bugfixes and code optimization to prevent LoS-related Jank

Enhanced Mod<>Mod Compatibility and added a new Second Wave Option, A Golden Requiem, which modifies Story Mission Enemy spawning.

Fixed an issue that stemmed from having borrowed some code from Long War Of The Chosen that turned out to be janky, and could result in some Cohesion bonuses not tracking properly.

Fixed a minor localization error

Made Requiem Corrosion a bit more forgiving early on.
Added A Merciless Alteration Second Wave Option, AKA Hard Mode.

Small AI Bugfixes
Gunships will no longer have incorrect stats on some difficulty settings.

UI Icon Enhancement courtesy of Evilbob
Small AI fixes

Fixed some unit variations not properly showing the Requiem Pink Healthbars with the requisite mod

Small Assorted Bugfixes
Removed Niven Stun Immunity
Added Gunship Variations

Major Balance and Mechanical Tweaks Patch

Significantly modified stats for a large number of Units
Modified Some Spawning FLs
Large Damage Number Tweaks
Implemented Squad Cohesion Mechanics For Enemy Squads in Which Requiem Legion Units are spawned.