Get rid of engine parameters no longer used

[johndoknjas]

The self._parameters dict has a few options that don't appear in current Stockfish's options list. Namely:

• "Contempt" - removed from the Stockfish source in commit ed436a3, on June 16, 2021.
• "Min Split Depth" - removed from the Stockfish source in commit 307a5a4, on Oct 24, 2015.
• "Minimum Thinking Time" - removed from the Stockfish source in commit 208c53d, on June 24, 2020.

Continuing to call the stockfish engine with setoption for any of these won't crash the engine. In the terminal it simply says it's not an option, and continues running fine. However, having the user believe these are still options in use of course isn't good. Removing a recent option could be unideal though, if a user is using a version of Stockfish that still had that option.

A middleground would be adjusting self._parameters based off the version of Stockfish the user is using, but maybe this introduces too much complexity into the code.