Vehicle (partial) customization project

检查 FixedEquipment 的 vehiclechassisdefs 处理，以及所请求的 AllowedLocationsOverride 和 CustomWeights 行为。确认关键请求和可选请求中的哪些内容属于范围，然后通过车辆自定义行为和兼容性验证来定义完成标准；该 issue 未指定源文件或测试。

Creating an issue on github as reuqested to not loose this in ticktes

Critical issues - this project cannot proceed without this implemented

1. Fixed gear
   vehiclechassisdefs do not process "FixedEquipment": [] block at all - i tried putting it in on some vee, its just ignored
   we need ME to either implment it or some custom that replaces it for vees
2. AllowedLocations override
   locations on fakevees do not match locations on mechs, so AllowedLocations on gear makes their placements on vees invalid
   we need a custom for gear that overrides AllowedLocations by UnitType
   something like
   "Custom": {
   "AllowedLocationsOverride": [
   {
   "UnitType": X
   "AllowedLocations": A
   }

Not Critical, but will real helps our sanity:)
RedBat's tools we currenyly use to validate vees is using this custom in vehiclechassisdefs to override weight of a gear installed
"CustomWeights": [
{
"ComponentDefID": "Gear_Vehicle_Compartment_Infantry_BA2",
"Tonnage": 8
}
]
would be realy nice if ME implements this in game too, will save us from creating hundred of copies of the same infantry and cargo bays with different weights

Maybe Maybe nice to haves - something we might use if its available, but we can go without this

1. ArmorLock - some custom flag in chassisdef that prevent player from modifiying unit armor in mechbay. Idk if implementing this is ever possibvle in light of compatibility with ArmorRepair mod
2. Vehicle/ProtoMech heatsink TT validation
   TT rules for vehicle and protomech heatsink are this
   unit must mount enough heatsinks to cover heatgen from all of its energy weapons. Only energy weapons matter, other types dont even if they generate heat