[examples] Clean up examples (#8674)

Move various "examples" into snippets. Several examples that were less
than a full mechanism or robot were moved to snippets. `arcadedrive` and
`tankdrive` were removed in favor of their Gamepad variants. `hidrumble`
was removed due to being too simple. `potentiometerpid` was removed
because of low utility. `gyromecanum` replaced `mecanumdrive` for
deduplication and because very few teams run holonomic drivetrains
without gyros.

wpilibcExamples/src/main/cpp/snippets/DigitalCommunication/include/Robot.hpp

@@ -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 <array>
+
+#include "wpi/framework/TimedRobot.hpp"
+#include "wpi/hardware/discrete/DigitalOutput.hpp"
+
+/**
+ * This is a sample program demonstrating how to communicate to a light
+ * controller from the robot code using the roboRIO's DIO ports.
+ */
+class Robot : public wpi::TimedRobot {
+ public:
+  // define ports for communication with light controller
+  static constexpr int kAlliancePort = 0;
+  static constexpr int kEnabledPort = 1;
+  static constexpr int kAutonomousPort = 2;
+  static constexpr int kAlertPort = 3;
+
+  void RobotPeriodic() override;
+
+ private:
+  wpi::DigitalOutput m_allianceOutput{kAlliancePort};
+  wpi::DigitalOutput m_enabledOutput{kEnabledPort};
+  wpi::DigitalOutput m_autonomousOutput{kAutonomousPort};
+  wpi::DigitalOutput m_alertOutput{kAlertPort};
+};