add setting for overriding pixel format in capture component

[zimmy87]

Fixes: #4339

About

This PR undoes #4321 and adds a new setting that allows the user to override the pixel format that each capture component in a camera is initialized with. This allows us to support scenarios where pixel format is expected to be either int or float. See #4339, #4120 and #4321 for more information about various scenarios that are impacted by pixel format selection. The new settings include a "UnrealEngine" setting, which contains a "PixelFormatOverride" setting, which then contains a list of settings that have both a "ImageType" and "PixelFormat" parameter. See test settings used below for an example of these settings being defined.

How Has This Been Tested?

The high_res_camera.py script, both with its original text and with ImageRequest.pixels_as_float = True, was used in conjunction with both the settings detailed in the test script as well as the modified settings below:

{
    "SettingsVersion": 1.2,
    "SimMode": "Multirotor",
    "Vehicles" : {
        "Drone1" : {
            "VehicleType" : "SimpleFlight",
            "AutoCreate" : true,
            "Cameras" : {
                "high_res": {
                    "CaptureSettings" : [
                        {
                            "ImageType" : 0,
                            "Width" : 4320,
                            "Height" : 2160
                        }
                    ],
                    "X": 0.50, "Y": 0.00, "Z": 0.10,
                    "Pitch": 0.0, "Roll": 0.0, "Yaw": 0.0
                },
                "low_res": {
                    "CaptureSettings" : [
                        {
                            "ImageType" : 0,
                            "Width" : 256,
                            "Height" : 144
                        }
                    ],
                    "X": 0.50, "Y": 0.00, "Z": 0.10,
                    "Pitch": 0.0, "Roll": 0.0, "Yaw": 0.0
                }
            }
        }
    },
    "UnrealEngine": {
        "PixelFormatOverride": [
            {
                "ImageType": 0,
                "PixelFormat": 10
            }
        ]
    }
}

Screenshots (if appropriate):

[rajat2004]

I guess the new element UnrealEngine is added for future inclusion of such UE-specific settings? Just thinking whether this might be more appropriate in CameraDefaults section, but no strong preference either way

[zimmy87]

@rajat2004, as per the UnrealEngine setting, you are correct, this is meant to be used as a container for all Unreal-specific settings. I have moved this to the CameraSetting element, that way we can specify it in CameraDefaults or only in desired cameras defined elsewhere.

[jonyMarino]

Thanks, @zimmy87! and thanks @rajat2004 for the review!