acme challenges must be answered by default_server

The challenge must be answered even before app nginx config
is available.

setup/start/nginx/appconfig.ejs

@@ -14,7 +14,7 @@ server {
 <% if (vhost) { -%>
     server_name  <%= vhost %>;
 <% } else { -%>
-    # IP based access. TODO: match the IPv6 address
+    # IP based access from collectd or initial cloudron setup. TODO: match the IPv6 address
     server_name  "~^\d+\.\d+\.\d+\.\d+$";
 
     # collectd
@@ -24,12 +24,6 @@ server {
         allow 127.0.0.1;
         deny all;
     }
-
-    # acme challenges
-    location /.well-known/acme-challenge/ {
-        default_type text/plain;
-        alias /home/yellowtent/platformdata/acme/;
-    }
 <% } -%>
 
     location / {