This patch generalizes node tree subtypes to be usable for node trees
other than Geometry Nodes. In particular, this:
- Renames SpaceNode.geometry_nodes_type to node_tree_sub_type, which now
store a tree type-specific enum.
- Renames SpaceNode.geometry_nodes_tool_tree to selected_node_group,
which now stores any context-less tree of any type.
This breaks the python API due to renaming.
Pull Request: https://projects.blender.org/blender/blender/pulls/144544
3d7c8d022e