Geometry Nodes: SDF Volume nodes milestone 1
Adds initial support for SDF volume creation and manipulation.
`SDF volume` is Blender's name of an OpenVDB grid of type Level Set.
See the discussion about naming in #91668.
The new nodes are:
- Mesh to SDF Volume: Converts a mesh to an SDF Volume
- Points to SDF Volume: Converts points to an SDF Volume
- Mean Filter SDF Volume: Applies a Mean Filter to an SDF
- Offset SDF Volume: Applies an offset to an SDF
- SDF Volume Sphere: Creates an SDF Volume in the shape of a sphere
For now an experimental option `New Volume Nodes` needs to be
enabled in Blender preferences for the nodes to be visible.
See the current work plan for Volume Nodes in #103248.
Pull Request: blender/blender#105090
