⚡ Simplify TaperedEvaluationTermByRank

[eduherminio]

• Remove duplicated backing field
• Make inner list an array

Getter properties need to remain for automatic configuration binding purposes.

This is a code simplification that might imply a speed up in practice

[-5, 0], 8+0.08

Score of Lynx-simplify-taperedevaluationtermbyrank-2996-win-x64 vs Lynx 2980 - main: 1383 - 1294 - 1771  [0.510] 4448
...      Lynx-simplify-taperedevaluationtermbyrank-2996-win-x64 playing White: 976 - 369 - 879  [0.636] 2224
...      Lynx-simplify-taperedevaluationtermbyrank-2996-win-x64 playing Black: 407 - 925 - 892  [0.384] 2224
...      White vs Black: 1901 - 776 - 1771  [0.626] 4448
Elo difference: 7.0 +/- 7.9, LOS: 95.7 %, DrawRatio: 39.8 %
SPRT: llr 2.89 (100.1%), lbound -2.25, ubound 2.89 - H1 was accepted