Request support for board uStepper S based stepper driver and encoder

[smukkejohan]

Please add support for uStepper S made by ON Development (https://www.ustepper.com/)

uStepper S is an Arduino compatible board, with integrated stepper driver and 16-bit rotary encoder, mounted directly on the back of a NEMA 17 size stepper motor.

• Uses a 328PB MCU
• Installation instructions for use with Arduino IDE here as well as all relevant src code https://github.com/uStepper/uStepperS