[examples] Adding XRP java and cpp examples for Timed Robot (#8599)

Adding an example (one C++ and one Java) for using TimedRobot with the
XRP.

wpilibcExamples/src/main/cpp/examples/Xrptimed/include/Robot.h

@@ -0,0 +1,31 @@
+// 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.
+
+#pragma once
+
+#include <frc/TimedRobot.h>
+#include <frc/Timer.h>
+#include <frc/XboxController.h>
+#include <frc/drive/DifferentialDrive.h>
+#include <frc/xrp/XRPMotor.h>
+
+class Robot : public frc::TimedRobot {
+ public:
+  Robot();
+  void RobotPeriodic() override;
+  void AutonomousInit() override;
+  void AutonomousPeriodic() override;
+  void TeleopInit() override;
+  void TeleopPeriodic() override;
+
+ private:
+  frc::XRPMotor m_leftMotor{0};
+  frc::XRPMotor m_rightMotor{1};
+  frc::XboxController m_XboxController{0};
+  frc::Timer m_timer;
+
+  frc::DifferentialDrive m_drive{
+      [&](double output) { m_leftMotor.Set(output); },
+      [&](double output) { m_rightMotor.Set(output); }};
+};