Added 3-phase stepper motor and AC motor with delta configuration.

Wrote a MATLAB script to enable rotating coil symbols 120 degrees. Seems that many symbols in Motor library are violating S3.1, and my new symbols looks symmetric so I didn't try to fix that.

About 3-phase stepper motor: https://www.trinamic.com/fileadmin/assets/Support/Appnotes/AN030-TMC5062_3_Phase_Motor.pdf 3-phase AC motor is very common so no datasheet is needed I think.

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