Return the relevance/score for other retrieval strategies

[tomlynchRNA]

e.g. in time weighted, we do:

    def format_results(self, results):
        self.logger.debug(f"{self.__class__.__name__} results: {results}")
        return "\n".join(
            map(lambda x: x if type(x) is str else str({
                'data': x[0].page_content,
                'metadata': x[0].metadata,
                'time_weight_score': x[1]
            }), results))

because each result is a tuple with [1] containing the relevance. Add the relevance to other retrieval strategies and return it in a similar format (but call it "score" instead of "time_weight_score")