[robotpy][examples] Split examples and snippets (#8944)

This also updates the bazel scripts to behave more like the C++ and Java
examples, and updates the copybara scripts to be able to sync up
`mostrobotpy`

robotpyExamples/examples/ArmSimulation/robot.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+#
+# 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.
+#
+
+import wpilib
+
+from constants import Constants
+from subsystems.arm import Arm
+
+
+class MyRobot(wpilib.TimedRobot):
+    """This is a sample program to demonstrate the use of arm simulation with existing code."""
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.arm = Arm()
+        self.joystick = wpilib.Joystick(Constants.kJoystickPort)
+
+    def simulationPeriodic(self) -> None:
+        self.arm.simulationPeriodic()
+
+    def teleopInit(self) -> None:
+        self.arm.loadPreferences()
+
+    def teleopPeriodic(self) -> None:
+        if self.joystick.getTrigger():
+            # Here, we run PID control like normal.
+            self.arm.reachSetpoint()
+        else:
+            # Otherwise, we disable the motor.
+            self.arm.stop()
+
+    def disabledInit(self) -> None:
+        # This just makes sure that our simulation code knows that the motor's off.
+        self.arm.stop()