Create bindings for webgpu

[Navigator class](https://github.com/scala-js/scala-js-dom/blob/7d0508cac24b4f2657c3525797fe633feb4849bc/dom/src/main/scala/org/scalajs/dom/Navigator.scala#L19) is missing the api for webgpu as described in the specs [here](https://gpuweb.github.io/gpuweb/#navigator-gpu)