Update to challenge LF, LFV evaluation code

We are going to roll out an improvement to the LF and LFV challenges competitions. This change fixes the following problems:

• The robot will always start in the right lane - a legal position.
• The evaluation and visualization code are going to be richer, with more statistics plotted (example).
• The evaluation rulebook is slightly changed to address a couple of bugs of how the metrics were computed.

What is going to happen is the following:

• The moment that we update the evaluation code, all existing submissions are set back to the state of "evaluation".
• The evaluators will then re-evaluate all of them. This will take 2-3 hours.

During this time the leaderboards are going to be blank, and slowly will re-populate as the evaluators do their job. (To speed up evaluation of your submissions, you can run dts challenges evaluator.)