Rank candidate players based off their match history

[will-hou]

Currently, candidate players that have fewer matches are equally likely to be placed into the next match as players that have played more matches. This can lead to the creation of extremely long match schedules and hinder algorithm performance.

To get around this, we can rank candidate players depending on when they were added to the list of candidates. Candidates added earlier are guaranteed to play in the next match. Candidates added later are less likely to play.