conf(nginx): change forwarded header removing host (PROJQUAY-8024) (q…

…uay#3327)

According to HCP support, the Ingress Load Balancer rejects requests
with a `host=...;` in the `forwarded` Header.

The PR changes that only the originating Client ($remote_addr) is
injected in the request as

```
Host: ....
Forwarded: for=127.0.0.1;
...
```

conf/nginx/server-base.conf.jnj

@@ -91,6 +91,7 @@ location ~ ^/_storage_proxy/([^/]+)/([^/]+)/([^/]+)/(.+) {
     proxy_set_header Host $3;
     proxy_set_header Authorization "";
     proxy_set_header x-forwarded-host "";
+    proxy_set_header forwarded "for=$remote_addr;";
     proxy_ssl_name $3;
     proxy_ssl_server_name on;