[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/SwerveBot/drivetrain.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 math
+import wpilib
+import swervemodule
+import wpimath
+
+kMaxVelocity = 3.0  # 3 meters per second
+kMaxAngularVelocity = math.pi  # 1/2 rotation per second
+
+
+class Drivetrain:
+    """
+    Represents a swerve drive style drivetrain.
+    """
+
+    def __init__(self) -> None:
+        self.frontLeftLocation = wpimath.Translation2d(0.381, 0.381)
+        self.frontRightLocation = wpimath.Translation2d(0.381, -0.381)
+        self.backLeftLocation = wpimath.Translation2d(-0.381, 0.381)
+        self.backRightLocation = wpimath.Translation2d(-0.381, -0.381)
+
+        self.frontLeft = swervemodule.SwerveModule(1, 2, 0, 1, 2, 3)
+        self.frontRight = swervemodule.SwerveModule(3, 4, 4, 5, 6, 7)
+        self.backLeft = swervemodule.SwerveModule(5, 6, 8, 9, 10, 11)
+        self.backRight = swervemodule.SwerveModule(7, 8, 12, 13, 14, 15)
+
+        self.imu = wpilib.OnboardIMU(wpilib.OnboardIMU.MountOrientation.FLAT)
+
+        self.kinematics = wpimath.SwerveDrive4Kinematics(
+            self.frontLeftLocation,
+            self.frontRightLocation,
+            self.backLeftLocation,
+            self.backRightLocation,
+        )
+
+        self.odometry = wpimath.SwerveDrive4Odometry(
+            self.kinematics,
+            self.imu.getRotation2d(),
+            (
+                self.frontLeft.getPosition(),
+                self.frontRight.getPosition(),
+                self.backLeft.getPosition(),
+                self.backRight.getPosition(),
+            ),
+        )
+
+        self.imu.resetYaw()
+
+    def drive(
+        self,
+        xVelocity: float,
+        yVelocity: float,
+        rot: float,
+        fieldRelative: bool,
+        periodSeconds: float,
+    ) -> None:
+        """
+        Method to drive the robot using joystick info.
+        :param xVelocity: Velocity of the robot in the x direction (forward).
+        :param yVelocity: Velocity of the robot in the y direction (sideways).
+        :param rot: Angular rate of the robot.
+        :param fieldRelative: Whether the provided x and y velocities are relative to the field.
+        :param periodSeconds: Time
+        """
+        chassisVelocities = wpimath.ChassisVelocities(xVelocity, yVelocity, rot)
+        if fieldRelative:
+            chassisVelocities = chassisVelocities.toRobotRelative(
+                self.imu.getRotation2d()
+            )
+
+        chassisVelocities = chassisVelocities.discretize(periodSeconds)
+
+        velocities = wpimath.SwerveDrive4Kinematics.desaturateWheelVelocities(
+            self.kinematics.toSwerveModuleVelocities(chassisVelocities),
+            kMaxVelocity,
+        )
+
+        self.frontLeft.setDesiredVelocity(velocities[0])
+        self.frontRight.setDesiredVelocity(velocities[1])
+        self.backLeft.setDesiredVelocity(velocities[2])
+        self.backRight.setDesiredVelocity(velocities[3])
+
+    def updateOdometry(self) -> None:
+        """Updates the field relative position of the robot."""
+        self.odometry.update(
+            self.imu.getRotation2d(),
+            (
+                self.frontLeft.getPosition(),
+                self.frontRight.getPosition(),
+                self.backLeft.getPosition(),
+                self.backRight.getPosition(),
+            ),
+        )