Documentation for PROXY protocol and rewriting client IP

[sjberman]

As an NGF user,
I want to know how to rewrite my client IP,
so that I can preserve the client IP through requests.

Acceptance

• Add documentation to describe configuring PROXY protocol and rewriting client IP

Question

• Should this be a standalone doc or an additional section in the data plane configuration doc?
  • Probably data plane configuration since the setting is contained within NginxProxy