Add ForwardedRequestCustomizer

[devinrsmith]

This allows jetty to correctly handle x-forwarded-* headers.

$ curl -H "x-forwarded-proto: https" -H "x-forwarded-host: example.com" -I http://localhost:10000
HTTP/1.1 302 Found
Date: Mon, 06 Feb 2023 02:41:34 GMT
Location: https://example.com/ide/
Content-Length: 0
Server: Jetty(11.0.13)

Without this patch, we would get Location: http://localhost:10000/ide/

[niloc132]

Approved, but where do we consume these, what's the use case or handler for this?

[devinrsmith]

I've got a couple of different reverse proxy setups - depending on if you requested the full /ide/ path, or something like /ide, you'd get a redirect and it would ship you back to http. I'm not 100% sure what the "correct" thing to do, or if there is even a definitive standard in this space. Some proxies might "fix" a misbehaving server, but other proxies might assume the "server knows best", and so proceed w/ the "bad" Location.