Part Default Installation Handler

# Installation Handler Overview
Name: Default Installation Handler
Function: adds the ability to install parts in the old scheme
From FVTM: yes

This Installation handler allows you to setup with which vehicles
your part is compatible, which parts the vehicle needs for this part
to be able to be installed and which part this one cannot be installed with.

If you want the part to be just installable, anywhere, without special
settings, just set "Installation": "default" in the Part config!

You can also set a per-vehicle specific "offset" of where the part will be rendered.

Example config (taken from FVP):

{
    "__comment": "Part JSON file.",
    "Installation": "default"
}
OR
{
    "__comment": "Part JSON file.",
    "Installation": {
        "Handler": "default",
        "Removable": true,
        "CustomCategory": false,
        "Compatible": [
            { "vehicle": "mypack:mycoolcar", "x": 0, "y": 23, "z": 14 },
            { "vehicle": "otherpack:good_truck", "x": 12, "y": 5.6, "z": 19.2 }
        ],
        "Incompatible":[
            { "vehicle": "mypack:mycoolcar", "parts": [ "bumper", "front_deco" ] },
            { "vehicle": "otherpack:good_truck", "parts": [ "some_part_category" ] }
        ],
        "Required": [
            { "vehicle": "mypack:mycoolcar", "parts": [ "lights", "hood" ] }
        ]
    }
}

Here an overview of the available fields:

• Handler - the id of the wanted handler, it is default
• Removable - (boolean) optional, if the part can be afterwards removed from the vehicle
• CustomCategory - (boolean) optional, if the part can be installed into a player specified category
• Compatible - optional, this is an JSON array with the compatible vehicles and offsets listed
  (each a JSON object)
  • e.g. { "vehicle": "<packid>:<vehicleid>", "x": x, "y": y, "z": z}
    • vehicle - the unique id of the vehicle
    • x - x coordinate of the seat, may/can be 0
    • y - y coordinate of the seat, may/can be 0
    • z - z coordinate of the seat, may/can be 0
• Incompatible - optional, this is an JSON array with the incompable parts per vehicle listed
  (each a JSON object)
  • e.g. { "vehicle": "<packid>:<vehicleid>", "parts": [ "categories", "here" ] }
    • vehicle - the unique id of the vehicle
    • parts - an string array with incompatible part categories
• Required - optional, this is an JSON array with the incompable parts per vehicle listed
  (each a JSON object)
  • e.g. { "vehicle": "<packid>:<vehicleid>", "parts": [ "categories", "here" ] }
    • vehicle - the unique id of the vehicle
    • parts - an string array with required part categories