Geometry Nodes: add Volume to Mesh node

This node takes a volume and generates a mesh on it's "surface".
The surface is defined by a threshold value.

Currently, the node only works on volumes generated by the
Points to Volume node. This limitation will be resolved soonish.

Ref T84605.

Differential Revision: https://developer.blender.org/D10243

release/scripts/startup/nodeitems_builtins.py

@@ -526,6 +526,7 @@ geometry_node_categories = [
     ]),
     GeometryNodeCategory("GEO_VOLUME", "Volume", items=[
         NodeItem("GeometryNodePointsToVolume"),
+        NodeItem("GeometryNodeVolumeToMesh"),
     ]),
     GeometryNodeCategory("GEO_UTILITIES", "Utilities", items=[
         NodeItem("ShaderNodeMapRange"),