Add timount on nginx configs

set timeout to 900
Signed-off-by: DQ <dengq@vmware.com>

make/photon/prepare/templates/nginx/nginx.http.conf.jinja

@@ -112,6 +112,9 @@ http {
       proxy_set_header X-Forwarded-Proto $scheme;
       proxy_buffering off;
       proxy_request_buffering off;
+
+      proxy_send_timeout 900;
+      proxy_read_timeout 900;
     }
 
     location /service/ {

make/photon/prepare/templates/nginx/nginx.https.conf.jinja

@@ -186,6 +186,8 @@ http {
       proxy_set_header X-Forwarded-Proto $scheme;
       proxy_buffering off;
       proxy_request_buffering off;
+      proxy_send_timeout 900;
+      proxy_read_timeout 900;
     }
 
     location /service/ {