Avoid large ELO descent for lower ranking AIs at the start of the season

[lladdy]

If an AI settles at an ELO lower than it's starting ELO (1600), then it's starting ELO is always the highest ELO in it's stats, rending the highest ELO stat meaningless

Discord user stephen raises the issue here: https://discord.com/channels/350289306763657218/350290846320427011/1167714744275308565

Some suggestions raised:

• Start AIs at a lower ELO
• have a bonus points pool awarded on wins that keeps total ELO @ num AIs * 1600
• Start an AI at it's last season's ELO if available.
• Set highest ELO only after a certain amount of rounds

[lladdy]

Crypt to investigate possible solutions.