Blender Git Loki

Geometry Nodes: Fill instances separately in the curve fill node

With this commit, each referenced instance data will be converted to
a geometry instances and processed separately. This should result in
a large speedup when the instances component has many insances
referring to the same data.

This change can act as a blueprint for other nodes that need to
implement similar behavior. It adds some helper functions on the
instances component to make that easier.

Thanks to Erik Abrahamsson for a proof of concept patch.

Differential Revision: https://developer.blender.org/D12572