Update to Godot 4

Hey!
I recently updated the code to use Godot 4.2. You can find the source in the downloads section, on GitHub, or in this post.

Tech-wise, I also changed all the shaders to use the same consistent color system (an array of vec4's), which required a whole bunch of rewriting.
I wanted to update the web version of the generator as well, but unfortunately it seems that Godot 4 .2 has very slow web loading times right now. I experimented a bit with the Godot 4.3 beta version, and that seems better. so new features will likely be coming to the web version of the pixel planet generator by then.

A new feature I'm planning on is to have rings be available for all planet types. Let me know if you want to see something else as well.

Thanks to everyone who is using and/or supporting the generator!
Cheers!