proxyauth: support basic auth

this is required for apps like transmission

src/nginxconfig.ejs

@@ -166,6 +166,8 @@ server {
         internal;
         proxy_pass http://127.0.0.1:3001/auth;
         proxy_pass_request_body off;
+        # repeat proxy headers since we addded proxy_set_header at this location level
+        proxy_set_header X-App-ID "<%= proxyAuth.id %>";
         proxy_set_header Content-Length "";
     }