Ball joint alternative for h pattern shifter controller

Replaced the ball joint in the h-pattern shifter, requires 2 additional bearings, m8 bolts and nuts.

The ball joint I ordered was delayed by a couple of months and all the locally available alternatives were expensive, so I modeled this up. Not sure on it's longevity, but it got me running.

Other differences from stock on my shifter - upgraded main carriage (see the other remix), and running inverted.

I've also included my gear knob, it's a single print (rather than multi part), screws directly on to the m8 rod, and is designed for LARGE hands, I'll re-export and upload with a smaller head if anyone requests.