[ARP] Follower race condition fixes, YAW_GAIN and PITCH_GAIN parameters, clockwise positive yaw

Added isInit variable to avoid step to run in case of non-initialized Follower.
targetAngle now protected with an apposite mutex to avoid race condition between the step and get functions.
Added pitch and yaw gain constexpr parameter
Fix yaw AntennaAngles old documentation assumption of counter-clockwise positive.