[xrp] Add Reflectance sensor and rangefinder classes (#5673)

Co-authored-by: Tyler Veness <calcmogul@gmail.com>

xrpVendordep/src/main/native/cpp/xrp/XRPReflectanceSensor.cpp

@@ -0,0 +1,15 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/xrp/XRPReflectanceSensor.h"
+
+using namespace frc;
+
+double XRPReflectanceSensor::GetLeftReflectanceValue() const {
+  return m_leftSensor.GetVoltage() / 5.0;
+}
+
+double XRPReflectanceSensor::GetRightReflectanceValue() const {
+  return m_rightSensor.GetVoltage() / 5.0;
+}