AppleWatch stand remix - USB cord improvements

Enlarged the rectangular hole for the USB-A connector 2) Enlarged and raised the cord retention features on the bottom so larger USB cables fit 3) Added ballast cavities on the bottom (no support needed) so weight can be glued-in to keep the base down when you take the watch off. This part could be further improved as it will take more than a few spare nuts/metal to counteract the force of the magnet on the watch.