Add MPEG lighting extensions

[haudiobe]

MPEG_lights_texture_based and MPEG_lights_punctual: When inserting virtual information in a captured real-world environment, lighting is a fundamental cue for providing a realistic experience to the user. Improper lighting and shadows can break the immersive illusion of the inserted virtual objects. In a VR context, accurate lighting models allow achieving a high level of realism. The MPEG-SD lighting extensions allow for dynamic lighting that is more like a video than a static source: coefficients like reflectance can change over time. The light sources can be of two natures: real or virtual. In both cases, the light sources may be represented by the same mathematical models (punctual light, ambient light, etc.).

[CLAassistant]

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1 out of 3 committers have signed the CLA.

✅ ibouazizi
❌ haudiobe
❌ lelievres
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[pzgulyas]

Isn't there an overlap with KHR_animation_pointers?