[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/snippets/IntermediateVision/robot.py

@@ -0,0 +1,20 @@
+#!/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
+
+
+class MyRobot(wpilib.TimedRobot):
+    """
+    This is a demo program showing the use of OpenCV to do vision processing. The image is acquired
+    from the USB camera, then a rectangle is put on the image and sent to the dashboard. OpenCV has
+    many methods for different types of processing.
+    """
+
+    def __init__(self):
+        super().__init__()
+        wpilib.CameraServer.launch("vision.py:main")