proxy-real-ip-cidr should be a list like whitelist-source-range

[damoon]

i would like to list trusted networks for forwarded-for headers. in my case cloudflares ips https://www.cloudflare.com/ips/.

the same methood of ,-seperation (in whitelist-source-range) could be used to list different (recursive) trusted network. https://github.com/kubernetes/ingress/blob/master/controllers/nginx/configuration.md#whitelist-source-range

the lines in the nginx template are https://github.com/kubernetes/ingress/blob/master/controllers/nginx/rootfs/etc/nginx/template/nginx.tmpl#L22 and https://github.com/kubernetes/ingress/blob/master/controllers/nginx/rootfs/etc/nginx/template/nginx.tmpl#L299

sorry, about my missing golang knowledge. i do not know what to do there to get the configmap and annotation data to the template.