Add NPU option

[reillyeon]

Now that the Chromium prototype supports passing "npu" in the context creation options we need samples that exercise this code path.

[huningxin]

This sounds good. AFAIK, @mingmingtasd has a fork enabling this path. Mingming, feel free to send out a PR for review.

/cc @ibelem

[fdwr]

Related:

• WebNN Spec issue to extend MLContextOptions::MLDeviceType.
• Chromium CR adding NPU device type

[mingmingtasd]

This sounds good. AFAIK, @mingmingtasd has a fork enabling this path. Mingming, feel free to send out a PR for review.

/cc @ibelem

Oh, sorry, missed this message, I will do.

[huningxin]

The image classification and object detection samples now support npu. Can we close this issue?