reverse: add ocsp stapling support

reverse/rootfs/nginx/conf.d/ocsp.conf

@@ -0,0 +1,4 @@
+ssl_stapling on;
+ssl_stapling_verify on;
+resolver 84.200.69.80 84.200.70.40 valid=300s;
+resolver_timeout 5s;

reverse/rootfs/nginx/sites-enabled/template_ssl

@@ -18,6 +18,7 @@ server {
   include /nginx/conf.d/ssl.conf;
   include /nginx/conf.d/headers.conf;
   include /nginx/conf.d/hsts.conf;
+  include /nginx/conf.d/ocsp.conf;
 
   include /nginx/path.d/<frontend_domain>/*.conf;