Add a drivetrain typescript plot config

Also, add a few extra comments/error messages to other pieces of
the plotting infrastructure.

Change-Id: Iab4dded93b1c5019e6b6c3d96d66728aa2e1f2a1
diff --git a/frc971/analysis/BUILD b/frc971/analysis/BUILD
index 0ef9bca..f378b68 100644
--- a/frc971/analysis/BUILD
+++ b/frc971/analysis/BUILD
@@ -95,6 +95,7 @@
         "//aos:configuration_ts_fbs",
         "//aos/network/www:demo_plot",
         "//aos/network/www:proxy",
+        "//frc971/control_loops/drivetrain:drivetrain_plotter",
         "//frc971/wpilib:imu_plotter",
     ],
 )