Add support for HTTP "Forwarded" header (RFC 7239)

Idea

This idea suggests to add support for the HTTP header "Forwarded", as described in RFC 7239.

The "Forwarded" header may eventually replace the HTTP header "X-Forwarded-For".

Explanation

Domino currently has already support for HTTP "X-Forwarded-For" header (XFF).

The XFF header can be used in Domino for security relevant settings, such as "Trusted Proxies" and "Internet Lockout".

However, the XFF header is not an official Internet Standard, and has no RFC assigned to it.

IETF has published RFC 7239, in which it suggests that the HTTP header "Forwarded" may be used for the same purpose, but in a formalized way, and also with additional features.

For example, a trusted proxy may be configured to obfuscate client IP's using the the "Forwarded" header, when forwarding HTTP requests to another server, in order to preserve privacy.

References:

https://en.wikipedia.org/wiki/X-Forwarded-For

https://datatracker.ietf.org/doc/html/rfc7239

[ Toni Feric, Belsoft Collaboration ]