Nikita Savelyev

@AlexanderDokuchaev thank you for your suggestions! Applied all except one

@daniil-lyakhov could you please review the PyTorch backend part of the implementation, specifically `PTSparsifyActivationsAlgoBackend` class?

Conformance test build (id=12) has passed. The time it takes is about half an hour. The only thing left is some documentation of the method.

@alexsu52, please take a look. The PR should be ready for merging. cc @AlexKoff88 @MaximProshin