Unify source of camera geometry data

Due to parallel development, camera pose information ended up being
populated in two constants files. This makes //y2019/vision:constants
the source for all of the constants.

Also, because the camera 19 calibration was done as if it was a front
camera, I had to negate its x/y position and offset the angle by 180
degrees.

This commit also adds validation for //y2019/vision:constants.cc to
ensure that it is not accidentally changed in a way that the codegen
cannot account for.

Change-Id: I85654d973e15ae7bf76589be63c3d0eaf72c3a45
diff --git a/y2019/vision/global_calibration.cc b/y2019/vision/global_calibration.cc
index 94048ad..186e025 100644
--- a/y2019/vision/global_calibration.cc
+++ b/y2019/vision/global_calibration.cc
@@ -247,7 +247,7 @@
   results.dataset = info;
   results.intrinsics = IntrinsicParams::get(&intrinsics[0]);
   results.geometry = CameraGeometry::get(&geometry[0]);
-  DumpCameraConstants(info.camera_id, results);
+  DumpCameraConstants("y2019/vision/constants.cc", info.camera_id, results);
 }
 
 }  // namespace y2019