Added PositionControl library (#2430)

This is a library aiming at implementing pid control to control the position of a DC motor with feedback from quadrature encoder using speed control driver

Author: Vishal Kumar

repositories.txt

@@ -5550,3 +5550,4 @@ https://github.com/khoih-prog/ContinuousStepper_Generic
 https://github.com/sparkfun/SparkFun_WM8960_Arduino_Library
 https://github.com/Beirdo/Arduino-FRAM-Cache
 https://github.com/mission-mangal/speed-control
+https://github.com/mission-mangal/PositionControl