This patch turns the options of the Bilateral Blur node into inputs.
In the process, the Sigma Space and Iterations were joined into a single
Size input, previously they were just added together then ceiled to get
the blur size. Furthermore, Sigma Color was renamed to threshold and now
represents the average color difference, not the sum, so it was
previously multiplied by 3.
Versioning and RNA compatibility is not perfect due to joining the two
size options.
Reference #137223.
Pull Request: https://projects.blender.org/blender/blender/pulls/138249
510130de07