Per-camera lighting

## Desired behavior
I need a way to selectively make lights visible per camera (but I do not want these lights visible in the "global" camera that sim gui uses). I need that to simulate multiple camera that bring their own light source and are pointed as the same or similar parts of my scene. Specifically I want to better simulate the intensity image of the Sick Visionary-T Mini. In reality these cameras capture images one after another and only have their light on when capturing images, so they do not interfere with one another.

## Implementation suggestion
Visuals already have a visibility mask. This could be used for lights, too, to implement this feature.

## Additional context
Currently a single directional light (sun) is used, but that has a quite large reality gap as the light intensity is homogeneous across the scene and thus the cameras. In reality these cameras have a bright spot at the image center and the intensity decreases towards the borders. Using per-camera lighting would reduce that reality gap.