Support HAProxy's Proxy Protocol

[OOTS]

Description

Support HAProxy's PROXY Protocol. This is useful when having TLS enabled and running behind a reverse proxy or load balancer. It would achieve something similar like setting Forwarded or X-Forwarded-For HTTP headers, but can (unlike those headers) also be used without giving the SSL certificate to the reverse proxy (or load balancer).

This was already proposed in #4227, but that issue was closed (and I'm not able to reopen it).

Implementation ideas

Create a configuration (e.g. quarkus.http.proxy.proxy-protocol) option that allows users to enable the PROXY protocol on the listener. It could be a boolean (with a default value of false). Call VertX's HttpServerOptions.setUseProxyProtocol() with the value provided in the configuration.