[wpilib][sim] Add Onboard IMU Sim (#8855)

This provides the ability to simulate parts of the Onboard IMU at the
HAL level. This allows team to use and simulate the IMU in code, and a
follow up PR could be made to the halsim_gui to add a new widget to view
and modify the data graphically.

Since the C++ IMU uses radians for angles that is what I did for the
simulator.

Partially deals with #8845

wpilibc/src/test/python/test_onboard_imu.py

@@ -0,0 +1,41 @@
+from wpilib import OnboardIMU
+from wpilib.simulation import OnboardIMUSim
+
+def test_sim_device() -> None:
+
+    imu = OnboardIMU(OnboardIMU.MountOrientation.FLAT)
+    sim = OnboardIMUSim()
+
+    assert 0.0 == imu.getAngleX()
+    assert 0.0 == imu.getAngleY()
+    assert 0.0 == imu.getAngleZ()
+    assert 0.0 == imu.getGyroRateX()
+    assert 0.0 == imu.getGyroRateY()
+    assert 0.0 == imu.getGyroRateZ()
+    assert 0.0 == imu.getAccelX()
+    assert 0.0 == imu.getAccelY()
+    assert 0.0 == imu.getAccelZ()
+    
+    sim.setAngleX(1)
+    sim.setAngleY(2)
+    sim.setAngleZ(3)
+    
+    sim.setGyroRateX(3.504)
+    sim.setGyroRateY(1.91)
+    sim.setGyroRateZ(22.9)
+    
+    sim.setAccelX(-1)
+    sim.setAccelY(-2)
+    sim.setAccelZ(-3)
+
+    assert 1.0 == imu.getAngleX()
+    assert 2.0 == imu.getAngleY()
+    assert 3.0 == imu.getAngleZ()
+
+    assert 3.504 == imu.getGyroRateX()
+    assert 1.91 == imu.getGyroRateY()
+    assert 22.9 == imu.getGyroRateZ()
+
+    assert -1.0 == imu.getAccelX()
+    assert -2.0 == imu.getAccelY()
+    assert -3.0 == imu.getAccelZ()