MatMulInteger op is partially supported

[gyulaz-htec]

MatMulInteger op can accept uint8 and int8 types as inputs, but only int8 is supported.
MatMulInteger is parsed as quant_dot which has a restriction about that inputs should be int8, but it should allow uint8 as well.
Also the a_zero_point and b_zero_point optional inputs are not handled in MIGraphX.

MatMulInteger is needed for the BERT-Squad int8 onnx zoo model.
At the moment it fails with the following (I've used the changes from this PR to pass through an unimplemented operator):
what(): /code/AMDMIGraphX/src/include/migraphx/check_shapes.hpp:210: same_type: quant_dot: Types do not match

Actions required:

• Update MatMulInteger implementation to accept uint8 type for T1 and T2 inputs
• Update MatMulInteger implementation to process a_zero_point and b_zero_point input tensors
• Don't forget to enable test_matmulinteger_cpu in onnx_backend:test.py

[gyulaz-htec]

Fixed in #2513