Add dispersion and caustics settings to Principled BSDF shader

In order to render out glass somewhat realistically, something called dispersion and caustics are needed.

Dispersion is much like chromatic aberration where the Red, Green and Blue channels are shifted but by their IOR (index of refraction) values.

This is commonly needed to make a good looking glass and should be part of the principled BSDF shader.

Caustics are how light organically disrupts the shadows in things like glass. Another feature which involves a lot of manual input. This one would be harder to achieve as right now, you need to enable caustics in multiple locations and then do some shader editing. This should be at most a 1 click enable in the scene and adjust the caustics settings in the Principled BSDF shader.

to help with this I can provide experience and design support but can't help with coding.