103 Early Hints support

[Ghostavio]

It would be nice to have support to 103 Early Hints for increased performance.

There has been some remix-run/remix#5378 regarding it back on Remix, but no final implementation.

With both caddyserver/caddy#5006 and Nginx supporting it would be great for my app running on react-router-serve to be able to serve the early hints as well.

[sergiodxa]

I think RR could add the Link tag to the responses, but ultimately using them to send a 103 Early Hint response first will depend on the HTTP server you use, as RR is a function called by an HTTP server and the ability to send two responses is also limited by what your HTTP server supports.

[Ghostavio]

In my case I'm serving my application through react-router-serve, so I'm suggesting having support when serving directly through RR.