implement uart configuration interface for tmc2209

[Sylensky]

This implements the configuration of the used tmc2209 stepper driver by applying the following settings via uart:

• IRUN: 1400mA (87% of 1.6A NEMA17 max) for strong torque for 4kg payload movement.
• IHOLD: 1120mA (80% of IRUN via 0.8 multiplier) for reliably position holding under heavy load.
• IHOLDDELAY: 12 cycles using extended delay before switching to hold current for load stability.
• TPOWERDOWN: 25 cycles for extended power-down delay for heavy load applications. Making it relatively long to avoid the driver entering the powerdown mode.

Additionally enable the 256 microstepping mode.

reqiures #68 and #70

[joaopedrotaveira]

Looks nice to me. great PR