⚡ Replace GameState with an internal State class inside of Position and an array of instances - Reset()

[eduherminio]

#2260 but using .Reset() instead of nee instantiations

⚡ Replace GameState with an internal State class inside of Position and an array of instances

Test  | refactor/gamestate-arrayinposition-2
Elo   | -0.55 +- 1.98 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -2.26 (-2.25, 2.89) [0.00, 3.00]
Games | 36620: +9654 -9712 =17254
Penta | [462, 3858, 9735, 3786, 469]
https://openbench.lynx-chess.com/test/2453/