Blender Git Loki

Geometry Nodes Curves: Refactor NURBS sampling

This is basically a template for a similar thing I'll do to bezier
splines. The idea is that every spline type is responsible for the
mapping of values from orginal control points to the evaluated
points based on a given resolution, and then the base class will
handle the rest.

This commit leaves the branch in a half-refactored state.