Reduce the possibility for one bot to block a competition with slow matches

[stephanzlatarev]

As commented in https://discord.com/channels/350289306763657218/350290846320427011/1161349232658235426 and the discussion that followed, a bot can block a competition with any behavior that leads to a tie at the 1-hour limit. We'd like the ladder to prevent this, and we have discussed ideas for changing the game rules (for example, grant a tie when a player runs out of army and supplies) or the competition rules (for example, skip a bot for next round if they block the previous round). I'm willing to prepare and test the required changes for a pull request. Please, assign me to this issue if you like this concern to be addressed and if you're OK with a newcomer to work on this matter (I'm willing to start with one of the "good first issue" before this one).

The suggested approach is when starting a new round for a competition to skip any bots with more than 10 pending matches in the active rounds for the same competition when the rest have 3 or less pending matches (as suggested by Infy). The number of bots that can be skipped (e.g. 1-2), the number of pending matches for those bots (e.g. 10), and the number of pending matches for the rest (e.g. 3) are to be configurable.

The implementation may exclude the bots to be skipped in this section: https://github.com/aiarena/aiarena-web/blob/main/aiarena/core/api/matches.py#L336-L339