PID tuning, add for Klipper

[maj-o]

Same calibration for Klipper is straight forward, just enter the following in the command line:

PID_CALIBRATE HEATER=extruder TARGET=200

when it's finished

SAVE_CONFIG

for the bed:

PID_CALIBRATE HEATER=heater_bed TARGET=60

when it's finished

SAVE_CONFIG