Score Transform for filter ensemble

We could have a "score transform" function hyperparameter for the ensemble so currently ensemble_score := sum_{filter i} scores_by_i * weight_i and then we could do ensemble_score := sum_{filter i} score_transform(scores_by_i) * weight_i inspired by https://github.com/ck37/featurerank/blob/56e1426ffac84d0512c9e7a502be535f6ea57f09/R/aggregators.R#L2 and @bblodfon