Add convert_move_to_user_inputs(g, move)

[richelbilderbeek]

Currently (and as part of #22) the game has instantaneous replay that does not check the UI:

void replayer::do_move(game& g)
{
  // ...
  const auto& move{m_replay.get_moves().at(move_index)};
  g.do_move(move);
  // ...
}

The replayer should use the UI:

void replayer::do_move(game& g)
{
  // ...
  const auto& move{m_replay.get_moves().at(move_index)};
  const user_input input{convert_move_to_user_input(g, move)};
  g.add_user_input(input);
  // ...
}