Ref implementation mvn revise (openvinotoolkit#6600)

* Add visitor and backend tests.

* Add reduction_axes to SLTs, serialization and backend tests.

* Update backend tests.

* Move backend tests to template plugin, remove old ones.

* Apply correct format.

* Add BF16 to SLT, add comment regarding deprecated class.

* Remove BF16 precision as it is not supported in windows, no default values for attributes.

* Reuse Tensor from base_reference_test.hpp

ngraph/python/requirements_test.txt

@@ -6,5 +6,5 @@ onnx==1.8.1
 pydocstyle==5.1.1
 pytest==6.1.2
 retrying==1.3.3
-tox==3.23.0
+tox==3.24.3
 wheel==0.36.2