Op to create quant scheme blob (#40760)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40760
Add op to create a quant scheme.
Test Plan:
buck test mode/opt caffe2/caffe2/quantization/server:int8_quant_scheme_blob_fill_test
{F241838981}
Reviewed By: csummersea
Differential Revision: D22228154
fbshipit-source-id: 1b7a02c06937c68e2fcccf77eb10a965300ed732
