Add support for area lights.

[catboy-catfish]

One of the features that Godot is missing right now is area lights. "Angular Distance" on OmniLight3Ds and SpotLight3Ds mention them. "This can simulate area lights to an extent."

I would appreciate if you could add that in for Godot Engine 4.4.

[AThousandShips]

Thank you for your proposal, consolidating in:

• Add support for specifying light sizes and shapes for specular reflections / area lights #1275