Add an example showing the creation of a toy PyBind11 extension for oneMKL using dpctl

[diptorupd]

oneMKL is an open-source implementation of the oneMKL Data Parallel C++ (DPC++) interface according to the oneMKL specification. The library provides backends for CUDA as well as Intel MKL. In addition, it is possible to dynamically select a backend based on a SYCL queue.

Our example should demonstrate how dpctl's infrastructure can be used to easily create a Python module for oneMKL.

A high-level design can we as follows:

• Expose the onemkl::gemm routine as matmul.
• Introduce convenience types mat and vec that are based on dpctl.tensor.usm_ndarray.
• The function should accept a SyclQueue, mat, and optionally a list of SyclEvent objects and return a SyclEvent object.
• Demonstrate the usage of SyclTimer to time execution.
• Demonstrate ways to print a matrix/vector by first copying them into Numpy.ndarray.
• Demonstrate ways to populate a matrix/vector.

[diptorupd]

Has been added a while back.