Merge remote-tracking branch 'origin/pytorch_matmul_substitution' int…

…o pytorch_matmul_substitution

# Conflicts:
#	model_compression_toolkit/core/pytorch/graph_substitutions/substitutions/matmul_decomposition.py
#	tests/pytorch_tests/model_tests/feature_models/matmul_test.py
#	tests/pytorch_tests/model_tests/test_feature_models_runner.py