poststartup script moved to extra container, non init

elasticsearch/values.yaml

@@ -194,7 +194,7 @@ extraContainers:
             name="${idx%%:*}"
             path="${idx##*:}"
             echo "[template-loader] Applying template: $name from $path..."
-            curl -X PUT "$ES_URL/_index_template/$name" \
+            curl -X PUT "$ES_URL/$name" \
               -H 'Content-Type: application/json' \
               --data-binary @"$path"
           done