Feature Request: Add dashboard entry to configure robot starting pose

[drsandytoes]

We should have a way to specify the robot starting pose via the dashboard. (Path planner does this automatically based on the starting point of your autonomous path.) That's useful for testing when you want to start the robot facing the amp, but still have the correct sense of field-relative forward/backward. It could also be useful for starting the robot in competitions where it's against the angled portion of the speaker. Right now, we depend on starting the robot with the front-to-back axis of the robot parallel to the field's x-axis.