638afb9bd4
This is essentially a huge refactor/extension of our existing RNA compare & copy code, since static override needs more advanced handling here. Note that not all new features are implemented yet, advanced things like collections insertion/deletion are still TODO (medium priority). This completes the ground work for overrides, remaining commits will be about UI and some basic/testing activation of overrides for a limited set of data-blocks & properties. For details see https://developer.blender.org/D2417