Similar to 2e6223d90f, but potentially 16 times more effective.
The new attribute is named "instance_transform". It isn't displayed in the
spreadsheet since that wouldn't really be useful. This simplifies a lot of
code since it doesn't have to handle transforms specially anymore. But
complexity is added in the store named attribute node and attribute input
node to keep the old "position" attribute working for compatibility.
Pull Request: https://projects.blender.org/blender/blender/pulls/118531
