Add CORS headers to /opds location

Add CORS headers for OPDS endpoint

Author: mekarpeles

docker/web_nginx.conf

@@ -134,6 +134,9 @@ server {
     }
 
     location = /opds {
+        add_header Access-Control-Allow-Origin "*" always;
+        add_header Access-Control-Allow-Methods "GET, OPTIONS" always;
+        add_header Access-Control-Allow-Headers "Content-Type" always;
         return 301 /opds/;
     }