feat: shrink the tt entry object size

[DeveloperPaul123]

Changes

• Switch from using i64 to i16 for Score.
• Due to above, shrink TranspositionTableEntry to 16 bits
• Fixed overflow issues when calculating score due to Score change
• Added a very basic TranspositionTable unit test. Will be expounded on if we ever implement tt buckets.
• Altered TranspositionTableEntry::new to take the zobrist hash in directly.

Elo   | 5.28 +- 4.25 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=1MB
LLR   | 2.97 (-2.94, 2.94) [0.00, 10.00]
Games | N: 7372 W: 1557 L: 1445 D: 4370
Penta | [84, 648, 2128, 724, 102]
https://developerpaul123.pythonanywhere.com/test/54/