* feature(nyz): add trueskill as league metric, naive elo calculator, fix game_env info bug

* fix(nyz): fix league player mutate bug

* fix(nyz): fix league unittest bug

* feature(nyz): add elo ranking in league metric env

* polish(nyz): modify fixed eval policy and trueskill init

* feature(nyz): add init main player in evaluation and fix stop_value bug

* style(nyz): rename test_league_metric to avoid pyc cache bug