Move PSQ score to Position

Move PSQ score to Position

This patch simplifies Position::do_move() by moving the PSQ score from
StateInfo to Position and updating it inside the put/remove/move_piece
functions.

The downside is that there is now slightly more computation done in
Position::undo_move(), but the fishtest results are Elo neutral.

Passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 78820 W: 15775 L: 15760 D: 47285
http://tests.stockfishchess.org/tests/view/5b1cd1d00ebc5902ab9c64ab

Passed LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 32966 W: 5716 L: 5615 D: 21635
http://tests.stockfishchess.org/tests/view/5b31e1230ebc5902b2e5a833

Closes https://github.com/official-stockfish/Stockfish/pull/1647

No functional change.