* nGraph-ONNX CI improvement

- Added parallel CI on many SKUs,
- Jenkinsfile written in Declarative Pipeline which allows displaying sequential stages for parallel branches in Blue Ocean
- Moved proper CI code to ngraph-onnx repository
- Moved base_image_builder to ngraph-onnx repository

* Fix license header

* try catch for git info retrieval

* Add unsupported ops to iGPU backend

* Revert previous change