include leaderboard navigation in url

[mschrimpf]

Currently when clicking on e.g. neural, the leaderboard updates to those scores, but the url does not. This means that refreshing the page resets the view and also that the view cannot be shared. E.g. users are currently not able to link to a specific group of scores. Let's update the url to the leaderboard navigation, e.g. https://www.brain-score.org/vision/average_vision/neural_vision/IT.
(Ideally we could even link to a specific benchmark but this requires a benchmark page which is a separate topic.)

[KartikP]

Related: #368