feat: add the implementation of Gemm operator on Cambricon

[bitzyz]

1. Add Cambricon CMake options
2. Implement Cambricon GEMM operator in src/cambricon/gemm/cnblas.h
3. Add MLU skip logic in tests/test_gemm.py (transpose operations not currently supported)
4. Add Cambricon test in examples/gemm/gemm.cc
5. Add protected member variable workspace_size_ to Operator class
6. Add Cmabricon common utils_func in src/cambricon/common.h

[bitzyz]