Disable filer UI in configuration (#5297)

* Add filer.ui.enabled configuration property

* Add filer.expose_directory_metadata to config

* Ammend commit

* Remove ShowUI reference

* Update all routes that allow directory metadata

* Add cmd flag to server.go

weed/server/filer_server_handlers_read_dir.go

@@ -18,6 +18,11 @@ import (
 // is empty.
 func (fs *FilerServer) listDirectoryHandler(w http.ResponseWriter, r *http.Request) {
 
+	if fs.option.ExposeDirectoryData == false {
+		http.NotFound(w, r)
+		return
+	}
+
 	stats.FilerHandlerCounter.WithLabelValues(stats.DirList).Inc()
 
 	path := r.URL.Path
@@ -95,4 +100,5 @@ func (fs *FilerServer) listDirectoryHandler(w http.ResponseWriter, r *http.Reque
 	if err != nil {
 		glog.V(0).Infof("Template Execute Error: %v", err)
 	}
+
 }