Create a BM25Retriever from a list of texts.
Args:
texts: A list of texts to vectorize.
metadatas: A list of metadata dicts to associate with each text.
ids: A list of ids to associate with each text.
bm25_params: Parameters to pass to the BM25 vectorizer.
preprocess_func: A function to preprocess each text before vectorization.
**kwargs: Any other arguments to pass to the retriever.