The functions have been copied from the WorkingPlane class. It makes sense to also have them available outside that class. The WorkingPlane class will later be updated to use these functions so that duplicate code is avoided.
Note that the default tolerance of the project_point_on_plane function is 1e-7. In the original projectPoint function it is sys.float_info.epsilon (too small for FreeCAD IMO).
This includes `arcs`, `circle_inversion`, `circles`, `circles_apollonius`,
`circles_incomplete`, `cuboids`, `edges`, `faces`, `fillets`,
`general`, `geometry`, `intersections`, `linear_geometry`,
`offsets`, `sort_edges`, `wires`.
These are added to the `draftgeoutils` Doxygen group so that
the functions contained in each module are listed appropriately
in the automatically generated documentation.