Reverse proxy support

[yangm97]

When a request contains either the X-Forwarded-For or Forwarded headers and the originating host is trusted, the client IP should be derived from there instead.

There needs to be a configuration option for trusting IPs, subnets and a wildcard for when you can't know the proxy IP/range beforehand (i.e. AWS CloudFront).

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Forwarded

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For

https://symfony.com/doc/current/deployment/proxies.html

https://expressjs.com/en/guide/behind-proxies.html