Add Control to Rotate Pulley Motor

[BID3D]

Printer model

MMU3

Describe the enhancement

Add a feature to allow user to control MMU pulley motor rotation. Feature would be enabled such that pulley motor could be rotated under user control. The feature would allow user to rotate the motor pulley such that each of the grub screws can be readily accessed for tightening. Currently there is no direct control for this pulley motor other than the load filament to MMU3. The user needs a manual method to precisely control the rotation of a motor pulley to affect maintenance of the pulleys and their grub screws.

Expected functionality

User can access this new feature to allow rotation of MMU pulley motor. User would be able to rotate control knob on printer to control the rotation of the motor pulley shaft. User can manually control the motor pulley shaft rotation.