* 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.
Co-authored-by: Robert Kimball <robert.kimball@intel.com>