Support a way to temporarily override the context from Python. - Added method `Context.temp_override` context manager. - Special support for windowing variables "window", "area" and "region", other context members such as "active_object". - Nesting context overrides is supported. - Previous windowing members are restored when the context exists unless they have been removed. - Overriding context members by passing a dictionary into operators in `bpy.ops` has been deprecated and warns when used. This allows the window in a newly loaded file to be used, see: T92464 Reviewed by: mont29 Ref D13126