[IE] Add Blob::createROI method (#882)

[IE] Add Blob::createROI method (#882)

* Add default implementation that throws exception.
* Implement `createROI` for `TBlob` and existing compound blobs.
* Use reference couting for TBlob memory buffer to prolong its life time for ROI blobs.
* Add private extension for ND ROI and use it as implementation detail for now:
  * Add `DimSlice` and `TensorSlice` structures for generic ND ROI support.
  * Add `make_roi_desc` function to create `TensorDesc` for ROI.