Draft: SCORU: refutation game

Context

This is the first draft of the refutation game.

• It still needs some refactoring and somewhat better testing.
• Some debugging functions are still exposed.
• Needs better documentation.

Manually testing the MR

dune exec src/proto_alpha/lib_protocol/test/pbt/refutation_game_pbt.exe

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR