Create game as spectator (#4281)

* refactoring

* allow for creation of games as spectator

allow setting the amount of games per user to none
remove limit on amount of games when creating a game as judge as
spectator

* refactor common/server_player.cpp

* do not close games with spectating host automatically

* remove check that filters out 0 player games

this check didn't really do anything, deleted games are removed before
it would be reached

* don't transfer host to spectators

this seems to cause a bug, also present on master

cockatrice/src/gamesmodel.cpp

@@ -278,8 +278,6 @@ void GamesModel::updateGameList(const ServerInfo_Game &game)
             return;
         }
     }
-    if (game.player_count() <= 0)
-        return;
     beginInsertRows(QModelIndex(), gameList.size(), gameList.size());
     gameList.append(game);
     endInsertRows();