⌛ Add score stability (pow formula with min depth)

[eduherminio]

This is same as #1214 but with the min depth

Test  | time/score-stability-5
Elo   | 2.18 +- 1.74 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=128MB
LLR   | 2.90 (-2.25, 2.89) [0.00, 3.00]
Games | 52836: +13409 -13078 =26349
Penta | [710, 6000, 12750, 6165, 793]
https://openbench.lynx-chess.com/test/1014/

Test  | time/score-stability-5
Elo   | 1.69 +- 4.77 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | 0.23 (-2.25, 2.89) [0.00, 3.00]
Games | 8834: +2477 -2434 =3923
Penta | [211, 1049, 1855, 1090, 212]
https://openbench.lynx-chess.com/test/1015/

#1214 passed STC