Option for cloud position

[LauraWebdev]

Hey there,

first of all, thank you for this project, I've been playing around with it for some time now and the results are really great!
I'm currently working on a small prototype "above the clouds" and adjusted the shader to render the clouds below the view (rather than always above).

I've made the adjustment by just negating the EYEDIR within the sky function. I was thinking maybe this could be expanded to a simple shader param, but I don't have enough experience with shader code yet to create a potential PR.

Godot_v4.0.2-stable_mono_win64_ZSrA1GPIEG.mp4