Support Fast CGI Backend Types

[f0o]

What are you trying to do

I want to serve an API via fcgi to avoid having to wrap it in another layer of proxing to speak HTTP to HAProxy

What HAProxy Ingress should do or how it should behave differently

Ideally it should leverage the fcgi functionality like outlined in https://www.haproxy.com/blog/load-balancing-php-fpm-with-haproxy-and-fastcgi/

https://cbonte.github.io/haproxy-dconv/2.1/configuration.html#10