adding wrapper for proxy header passing.

add a selection to the proxy editing page and passes that down into the templates.
Removed set_proxy_header from locations and moved to server directive. these will inherit down into locations if they are not defined there.

docker/rootfs/etc/nginx/conf.d/include/proxy.conf

@@ -1,5 +1,4 @@
 add_header       X-Served-By $host;
-proxy_set_header Host $host;
 proxy_set_header X-Forwarded-Scheme $scheme;
 proxy_set_header X-Forwarded-Proto  $scheme;
 proxy_set_header X-Forwarded-For    $remote_addr;