Fix LE cert renewal failures

LE contacts the server by hostname and not by IP. This means that
when installing and reconfiguring the app it hits the default_server
route since nginx configs for the app are not generated at.

When doing in the daily cert renew, the nginx configs exist and we
are unable to renew the certs.

setup/start/nginx/appconfig.ejs

@@ -26,6 +26,12 @@ server {
     }
 <% } -%>
 
+    # acme challenges (for cert renewal where the vhost config exists)
+    location /.well-known/acme-challenge/ {
+        default_type text/plain;
+        alias /home/yellowtent/platformdata/acme/;
+    }
+
     location / {
         # redirect everything to HTTPS
         return 301 https://$host$request_uri;