More in-depth training statistics

[ed1d1a8d]

It would be helpful to get more informative statistics during selfplay/victimplay training.

Useful statistics to track:

• Win rate
• Fraction of games won by resignation
• Win-margin
• Number of moves taken

It would be nice to be able to plot all of the above as a function of training epoch, with the following filters:

• Color
• Board size
• Whether game was won or lost

Checked items means we already have support for that feature in some capacity.

Some comments:

• It would be nice to code this up in a way that supports both training and match play (i.e. by calling the match command in KataGo).
• The notebooks in https://github.com/HumanCompatibleAI/go_attack/tree/main/notebooks may contain some useful code for parsing statistics from games.