Integrate RustNN into WebNN implementation status

[anssiko]

We should add https://rustnn.github.io/rustnnpt/ data to https://webmachinelearning.github.io/webnn-status/ as a new backend. Even if not shipping in a browser yet, it is considered valuable new implementation experience.

Source:

• https://github.com/rustnn/rustnnpt/
• webnn_status.json
• webnn-status.md

Longer term, when Firefox with RustNN and other browser implementations mature, we should migrate also this data to ML* in https://github.com/mdn/browser-compat-data/tree/main/api to be propagated to MDN.

Cc @tarekziade @ibelem