improvement(docker): avoid caching mounted json/yml/yaml assets (via #5151)

docker/cors.conf

@@ -0,0 +1,14 @@
+add_header 'Access-Control-Allow-Origin' '*' always;
+add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
+#
+# Custom headers and headers various browsers *should* be OK with but aren't
+#
+add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type' always;
+#
+# Tell client that this pre-flight info is valid for 20 days
+#
+add_header 'Access-Control-Max-Age' $access_control_max_age always;
+
+if ($request_method = OPTIONS) {
+  return 204;
+}