[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/MecanumDrivePoseEstimator/exampleglobalmeasurementsensor.py

@@ -0,0 +1,34 @@
+#
+# 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 random
+
+import wpimath
+import wpimath.units
+
+
+class ExampleGlobalMeasurementSensor:
+    """This dummy class represents a global measurement sensor, such as a computer vision
+    solution.
+    """
+
+    def __init__(self) -> None:
+        raise RuntimeError("Utility class")
+
+    @staticmethod
+    def getEstimatedGlobalPose(estimatedRobotPose: wpimath.Pose2d) -> wpimath.Pose2d:
+        """Get a "noisy" fake global pose reading.
+
+        :param estimatedRobotPose: The robot pose.
+        """
+        rand_x = random.gauss(0.0, 0.5)
+        rand_y = random.gauss(0.0, 0.5)
+        rand_rot = random.gauss(0.0, wpimath.units.degreesToRadians(30))
+        return wpimath.Pose2d(
+            estimatedRobotPose.x + rand_x,
+            estimatedRobotPose.y + rand_y,
+            estimatedRobotPose.rotation().rotateBy(wpimath.Rotation2d(rand_rot)),
+        )