Integration with wasm-bindgen and conversion to Result<T, JsValue>

[ten3roberts]

This would enable eyre Reports to be transparently converted to a js_sys::Error. The current workaround is to convert the Report to a string, and use that as an error, which will stringify the error chain, rather than converting it to a javascript error chain.

[mw2000]

any update on this? would love to not stringify my error chain when using wasm-bindgen