SCORU: Add refutation games

Owner: @yrg

Context

This introduces a refutation game on the SCORU project. It is based on the PVM specs in # !4343 .

It is in fact a functor that takes a PVM and produce a game. The game state at a certain point is

 type t = {
    turn : player;
    start_state : P.state;
    start_at : Tick_repr.t;
    player_stop_state : P.state;
    opponent_stop_state : P.state;
    stop_at : Tick_repr.t;
    current_dissection : Section_repr.dissection option;
  }

• The output of a game is {winner : player option; reason : reason}
• A client is a pair of an initial move and a next_move strategy.
• The game is run with a function that takes a starting tick, a starting state and a committer and a refuter client and produces an output.

  val run :
    start_at: Tick_repr.t ->
    start_state:P.state ->
    committer:('a * P.state, commit) client ->
    refuter:(P.state * commit, refutation) client ->
    outcome

Manually testing the MR

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

It is still in draft because I want to write another set of tests.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Provide automatic testing (see the testing guide).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR