⚡ Remove UCI hashfull command for performance reasons

[eduherminio]

Score of Lynx 1217 - no hashfull vs Lynx 0.15.0: 592 - 426 - 308  [0.563] 1326
...      Lynx 1217 - no hashfull playing White: 352 - 158 - 153  [0.646] 663
...      Lynx 1217 - no hashfull playing Black: 240 - 268 - 155  [0.479] 663
...      White vs Black: 620 - 398 - 308  [0.584] 1326
Elo difference: 43.7 +/- 16.5, LOS: 100.0 %, DrawRatio: 23.2 %
SPRT: llr 2.95 (100.1%), lbound -2.94, ubound 2.94 - H1 was accepted

[eduherminio]

Will revisit hashfull using either a counter when inserting or an approximation method