Tidy up cable tidy shape

Adjust the cable tidy body build up sequence and adjust the cut outs to remove sharp points where the screw lugs meet the main body.

After !448 (merged) we have sharp points where the circular cut-outs over the motor screws meet the main body of the cable tidies:

Here the shapes are changed to make the outlines smoother:

and for the Upright:

• print and check.

closes #414 (closed)