Blender Git Loki

Merge branch 'master' into temp-geometry-nodes-instance-collections

Geometry Nodes: pick between instancing collection and object

Geometry Nodes: initial collection instancing

Fix: replace ID_CO with ID_GR

Nodes: add Collection socket type

The implementation of this socket works almost the same as object sockets.

I did not define a color for this socket yet (it's black for now).