Move object runtime data to a separate header and allocate it separately
as `blender::bke::ObjectRuntime`. This is how node, mesh, curves, and
point cloud runtime data is stored.
Benefits:
- Allow using C++ types in object runtime data
- Reduce space required for Object struct in files
- Increase conceptual separation between DNA and runtime data
- Remove the need to add manual padding in runtime data
- Include runtime struct definition only in files that require it
Pull Request: https://projects.blender.org/blender/blender/pulls/113957
4bcdc57fc8