[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/ElevatorTrapezoidProfile/examplesmartmotorcontroller.py

@@ -0,0 +1,98 @@
+#
+# 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
+import enum
+
+
+class ExampleSmartMotorController(wpilib.MotorController):
+    """A simplified stub class that simulates the API of a common "smart" motor controller.
+    Has no actual functionality.
+    """
+
+    class PIDMode(enum.Enum):
+        kPosition = enum.auto()
+        kVelocity = enum.auto()
+        kMovementWitchcraft = enum.auto()
+
+    def __init__(self, port: int) -> None:
+        """Creates a new ExampleSmartMotorController.
+
+        Args:
+            port: The port for the controller.
+        """
+        super().__init__()
+        self._velocity = 0.0
+        self._inverted = False
+        self._leader = None
+
+    def setPID(self, kp: float, ki: float, kd: float) -> None:
+        """Example method for setting the PID gains of the smart controller.
+
+        Args:
+            kp: The proportional gain.
+            ki: The integral gain.
+            kd: The derivative gain.
+        """
+        pass
+
+    def setSetPoint(
+        self, mode: PIDMode, setpoint: float, arbfeedforward: float
+    ) -> None:
+        """Example method for setting the setpoint of the smart controller in PID mode.
+
+        Args:
+            mode: The mode of the PID controller.
+            setpoint: The controller setpoint.
+            arbfeedforward: An arbitrary feedforward output (from -1 to 1).
+        """
+        pass
+
+    def follow(self, leader: "ExampleSmartMotorController") -> None:
+        """Places this motor controller in follower mode.
+
+        Args:
+            leader: The leader to follow.
+        """
+        self._leader = leader
+
+    def getEncoderDistance(self) -> float:
+        """Returns the encoder distance.
+
+        Returns:
+            The current encoder distance.
+        """
+        return 0
+
+    def getEncoderRate(self) -> float:
+        """Returns the encoder rate.
+
+        Returns:
+            The current encoder rate.
+        """
+        return 0
+
+    def resetEncoder(self) -> None:
+        """Resets the encoder to zero distance."""
+        pass
+
+    def set(self, velocity: float) -> None:
+        self._velocity = -velocity if self._inverted else velocity
+
+    def get(self) -> float:
+        return self._velocity
+
+    def setInverted(self, isInverted: bool) -> None:
+        self._inverted = isInverted
+
+    def getInverted(self) -> bool:
+        return self._inverted
+
+    def disable(self) -> None:
+        self._velocity = 0.0
+
+    def stopMotor(self) -> None:
+        self._velocity = 0.0