[backtesting.py] Add better logging to understand trade logic

### Enhancement description Currently, it is impossible to know why a position was closed or opened without clear logs explaining the reasons. Also, a trade id to identify all trades is needed. ### Code sample ```python self.buy(log="The position was opened") self.sell(log="The position was opened") self.position.close(log="The position was closed because???") trade.sl(price=???, log="Take stop loss was reached") trade.tp(price=???, log="Take profit was reached") ``` ### Additional info, images _No response_