[Gh pages] Update QNN EP documentation (quantization/python APIs)

[adrianlizarraga]

Description

Preview: https://adrianlizarraga.github.io/onnxruntime/docs/execution-providers/QNN-ExecutionProvider.html#running-a-model-with-qnn-eps-htp-backend-python

• Adds QNN EP documentation:
  • Create a quantized QDQ model using python quantization utilities
  • Run quantized QDQ model on Windows ARM64 using python ORT APIs.
• Updates QNN EP provider options
• Adds list of supported ONNX operators
• Provides instructions for using the new arm64 python wheel

Motivation and Context

The aim is to make it easier for users to try QNN EP.

[jywu-msft]

thanks for this!
Should we add some requirements for the arm64 python wheel? I know there's been some confusion in the past on this. (x64 vs arm64 dependencies)
perhaps we can list the config we've tested on numpy == 1.25.2 or >=1.26.4, python 3.11, 3.12 (arm64)
on 8cx gen3 , known issue with installing onnx on arm64 etc.

[HectorSVC]

[HectorSVC]