regression tree based binning of cts features

[mb706]

https://github.com/yandex-research/rtdl-num-embeddings/blob/abf8a8b35854e4b06476bb48902096b0b58ffce2/package/rtdl_num_embeddings.py#L300

https://arxiv.org/abs/2203.05556#

Could either be its own pipeop or an extension of an existing binning pipeop