Moved in servo/components/webxr with servo/servo#35228

A safe Rust API that provides a way to interact with virtual reality and augmented reality devices and integration with OpenXR. The API is inspired by the WebXR Device API (https://www.w3.org/TR/webxr/) but adapted to Rust design patterns.

It's used in the WebXR implementation for the Servo browser, but can be used outside of Servo.

Some notes on our plans for this API: https://paper.dropbox.com/doc/Rust-webxr-plans--Ad8iXHKI15DKsFhfT3ufGiQiAg-xmqpUtCzy8yNMGWwUUxsz