Improve CLI error handling a bit
Reduce the number of *easy* ways to hit UB or an uncaught exception. This builds on Sopel's work on FEN validation.
Obviously SF is not and will never be a security boundary, but at least we can reduce the number of reports about uncaught `std::stoi` out of range, etc.
I also added a gentle fallback to `NumaConfig` specifically because that's something that (as a dev) I frequently set by hand in the CLI, but happy to revert if that's too annoying of a change.
closes https://github.com/official-stockfish/Stockfish/pull/6844
No functional change