Fix Kubernetes config provider for recent changes in Kub API

Kubernetes secret volumes are now mounted as read-only, so we have to write the files *only* via the Kub API

Fixes https://jira.coreos.com/browse/QUAY-911

conf/nginx/server-base.conf.jnj

@@ -99,6 +99,14 @@ location ~ ^/cnr {
     limit_req zone=repositories burst=10;
 }
 
+location ~ ^/api/suconfig {
+    proxy_pass   http://web_app_server;
+
+    # For suconfig, set our read timeout as super large for both DB migrations
+    # and awaiting for secrets to be updated.
+    proxy_read_timeout 2000;
+}
+
 location ~ ^/v2 {
     # If we're being accessed via v1.quay.io, pretend we don't support v2.
     if ($host = "v1.quay.io") {