Correection of the way to use arduinoJson structure, and cretio of a name attribute to use it as the key

Split motor.h into motor.h an motor.cpp, dding a few fuction (some setters missing and conversion) and adding comments.

changing forward_clockwise to _clockwise_equals_forward in motor.h (to fit the way to use it in syringefilled.h)

Changing the name of _retain_accel to _acceleration_mm_per_sec_per_sec in motor class (so it fit better and lt us know t unit)

 Deletion of setupJsonSyringe(filled) methods because they are repetitive of setter methods and would be called in the constructor, we don't need another method to do it.

manage_emergency to take it into account.

Creation of methods move (which manage movement of the motor) and volume_to_distance which convert a volume to a distance from the syringe model.