Automate leaderboard generation

[fsschneider]

To simplify updating the leaderboard, we could automate the leaderboard generation as follows:

1. Scoring creates a leaderboard.csv containing relevant info about benchmark scores, authors, descriptions, etc.
2. [Triggered by changes to leaderboard.csv] A GitHub action could automatically update the repository's README.md file to include the new leaderboard (with a timestamp and increment of the leaderboard's version). The GitHub action should only be triggered if the leaderboard.csv changes.

Or as a further step towards more automation, we could run step 1 automatically when PR to main or changes to /logs/.