* Helper function get_axes_mapping.

* Enhance Broadcast:v1 NUMPY broadcasting.

- Enable NUMPY broadcasting mechanism to work in bothdirections:
    target_shape <-> arg_shape

* Add opset1:squeeze and fix bug in reading squeezed axis idx.

* Fix and enhance downgrade pass for Broadcast:v1

* Use Broadcast:v1 in ONNX Expand operator.

* Replace Broadcast:v0 with v1 in some helper functions.

* Remove call to deprecated legacy_broadcasting helper function.

* Add helper get_axes_mapping_output function.

* Use directly Broadcast:v1 instead of helper function.

* Get back operators from v0 in helper function.

* Use helper function and some refactoring.

* Add legacy style broadcast helper function for opset1.

* User helper broadcasting function for arithmetic operators.

* Add empty axis only if its size is equal to one.

* Aplly review remarks:

- Rename broadcasting function deleting _values_ infix
- Remove variables used only once.
- Use STL library where possible.
- Remove unnecessary conditions.

* Add helper for Broadcast:v1.

* Fix merge artifact and force unsigned type for argument.

* Review. Add additional check for static output.

* Apply clang-format.

* Fix: call v0 ops in ngraph::builder namespace.

* Move opset1 boradcasting helpers from util/broadcasting.hpp

* Use autobroadcast built-in mechanism for arithmetic operators in RNN.

* Move helper functions to autobroadcast.hpp file.

- Update calls with new namespace ngraph::builder
- Remove calls using shared_ptr<ngraph::Node> and replace them with
  one accepting Output<ngraph::Node>
- Some small formatting (remove unnecesary namespace prefix)

* Remove unused function.

* Rename error class to reflect it's NumPy related.

* Fix thrown error name in autobroadcast UT.

* Code refactoring.

- Use one one set of helpers to broadcast node according to NumPy scheme

* Documentation formatting.

* Remove include to deleted header.

* Apply style format.

* Remove std:: prefix.

* Do reshape and/or broadcast only when necessary.

* Remove std:: and ngraph:: prefixes.

* UT for numpy_broadcast_for_matmul and legacy boradcast.

* Rename helper function.

* UT for opset1 legacy broadcast helper function.

* Add more UT for get_axes_mapping and style-format.

* Review comments.

* Restrict if with NGRAPH_WARN to NGRAPH_CHECK.
Co-authored-by: Michał Karzyński <postrational@users.noreply.github.com>
Co-authored-by: Sang Ik Lee <sang.ik.lee@intel.com>