onnxruntime

Merge CPU/GPU nuget pipeline (#8683)

Merge CPU/GPU nuget pipeline. The old GPU nuget pipeline will be only for DML.

TODO: the result GPU package contains PDB files for some of the DLLs, but not all. It is due to the refactoring of CUDA EP to pluggable DLLs. At that time we forgot to copy the PDB files. However, I can't add them in now. Because currently the package is already 220MB large. If the missed PDB files were added, then it will be oversize. nuget.org doesn't accept >250MB packages.