Implement score normalization technique as a post-processor

[AlekseySh]

The method is described here. The class has to be child of IRetrievalPostprocessor, take RetrievalResults as input, modify it, and return as a new instance of RetrievalResults class.

The plan is to implement the method and check if it boosts metrics on our real benchmarks (see existing datasets in Pipelines).

Unfortunately, our current metrics are not sensitive to the type of transformation performed by score normalization.
Thus, this issue of adding the appropriate sensitive metric has to be completed first.