⚡ Make search config params constant

[eduherminio]

Make search config params const, losing the abiliy to override them via appsettings.json (in exchange of let's see how much of a speedup/elo).

It wins, but worth merging 'only' for that elo?
It implies creating a mess for tuining, for instance

Test  | perf/constant-search-params
Elo   | 4.34 +- 3.46 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | 2.90 (-2.25, 2.89) [0.00, 5.00]
Games | 18726: +5996 -5762 =6968
Penta | [583, 2011, 4020, 2087, 662]
https://openbench.lynx-chess.com/test/448/

[eduherminio]

Requires thinking of a way of still configutable tunable UCI params