[onnx,onnx-optimizier] Remove "python3" dependency and "pybind11" feature

[luncliff]

Changes

• Remove python3 dependency in onnx installtion
• Remove pybind11 feature of onnx and onnx-optimizer

There are some concerns about pybind11 feature of 2 ports.

• To support BUILD_ONNX_PYTHON, we have to install pybind11 and protobuf python package
  • https://github.com/onnx/onnx/blob/b8baa8446686496da4cc8fda09f2b6fe65c2a02c/requirements-min.txt#L2-L3
  • Maybe we can use vcpkg-get-python-packages, but it can only "supports": "native"
• Currently, both onnx and onnx-optimizer doesn't install python module(binary) in CMake build
  • To be correct, we may need to support protobuf[python]. The source is using Bazel build for protobuf_python
    https://github.com/protocolbuffers/protobuf/blob/e3ac4c9342e5393e3fa974a420fc1bbc68e7397a/BUILD.bazel#L396-L400

it seems like there is no use of onnx-optmizier[pybind11] and onnx[pybind11].
And they became fragile to be maintained. I suggest removal of the pybind11 feature.

References

• Correct ONNX and Protobuf version in vcpkg build onnxruntime#23285
• [onnx] update to 1.14.1 luncliff/vcpkg-registry#116

Start of pybind11 feature

• [onnx] create a new port #18073
• [onnx-optimizer] create a new port #19258

Checklist

• Changes comply with the maintainer guide.
• SHA512s are updated for each updated download.
• The "supports" clause reflects platforms that may be fixed by this new version.
• Any fixed CI baseline entries are removed from that file.
• Any patches that are no longer applied are deleted from the port's directory.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

[Osyotr]

This is effectively vendoring pybind11.
If you want to use system python, use empty overlay for python3.

[luncliff]

I suggest removal of the pybind11 feature. Updated the PR note above.
Would you check it?

[luncliff]

If reviewers think onnx-optimizer change can be separated to comply with https://github.com/microsoft/vcpkg-docs/blob/main/vcpkg/contributing/maintainer-guide.md#make-separate-pull-requests-per-port
I will cherry-pick the related changes and separate the PR. Feel free to tell me.

[Neumann-A]

https://github.com/onnx/onnx/blob/321c1dc21b531ecb13965a3e912c6a4f60c6c206/INSTALL.md?plain=1#L216

If you run into any issues while building ONNX from source, and your error message reads, Could not find pythonXX.lib, ensure that you have consistent Python versions for common commands, such as python and pip. Clean all existing build files and rebuild ONNX again.

As such it requires python3 build by vcpkg.