Allow single agent, score only "games"

[StoneT2000]

For the type of "Kaggle" competitions where users submit a "agent" (or code) that then is run, and a score is produced and set as the leaderboard rank.

Require's a bit of hardcoding as this no longer uses rank states and relative ranks to compute new ranks, and there is no need to schedule matches anymore, its one match and done.