optimization: use client hints for SSR

[yocontra]

https://developers.google.com/web/updates/2015/09/automating-resource-selection-with-client-hints

We can use these new hint headers to get the actual constraints and use those values on the server instead of making an educated guess then doing a re-render on the client. Any user who enables these hints on their page would be able to benefit from the optimization, otherwise the current method still applies.

Would be a good PR!

[oyeanuj]

@contra Came here looking for this. Is this on the radar?

[yocontra]

@oyeanuj Yep - after we take care of #162 which will finalize the SSR API we can do this one.

[yocontra]

This doesn't seem to have gotten any more browser support since 2020 - no FF or Safari support. For that reason going to backburner this until it gets more adoption.

Also given the spec, this would only work w/ deviceWidth / width queries - which satisfies a lot of use cases but not all.