Add calibration tutorial to dozuki

[i-make-robots]

"I think you should make a calibration program on Robot Overlord, taking step by step the user through the calibration"

[i-make-robots]

"I think that first step would be to check that we receive well all sensors and motors (easier for the sensors I must say, I don’t know how you could do it with the motors without activating them…)

second step would be to activate each motor one by one with slow mouvements, checking DOF by DOF

then for the calibration it would be like be able to move the motors one by one until the user says « I am at home position, everything is aligned ».

Then the software saves the configuration and runs everything based on that zero."

[i-make-robots]

https://mcr.dozuki.com/Guide/11.+Calibrate+a+Sixi+robot/29?lang=en

[i-make-robots]

https://www.marginallyclever.com/2020/08/sixi-calibration-tool/

[i-make-robots]

Firmware dev branch now has D23 command to calibrate sensors. sets home position expecting the arm is at calibration point right now.

[i-make-robots]

Calibration block is fine in principle. too close to shoulder means it does not calibrate shoulder well.