fix flowfile name to flows.json in settings

and warn if not set (as if anyone reads warnings)
Move setting to top of settings.js as it will be edited more often.
Default behaviour will still work
(needs translations)

packages/node_modules/node-red/settings.js

@@ -12,6 +12,13 @@
  **/
 
 module.exports = {
+    // The file containing the flows. If not set, it defaults to flows_<hostname>.json
+    flowFile: 'flows.json',
+
+    // To enabled pretty-printing of the flow within the flow file, set the following
+    //  property to true:
+    //flowFilePretty: true,
+
     // the tcp port that the Node-RED web server is listening on
     uiPort: process.env.PORT || 1880,
 
@@ -61,13 +68,6 @@ module.exports = {
     // Colourise the console output of the debug node
     //debugUseColors: true,
 
-    // The file containing the flows. If not set, it defaults to flows_<hostname>.json
-    //flowFile: 'flows.json',
-
-    // To enabled pretty-printing of the flow within the flow file, set the following
-    //  property to true:
-    //flowFilePretty: true,
-
     // By default, credentials are encrypted in storage using a generated key. To
     // specify your own secret, set the following property.
     // If you want to disable encryption of credentials, set this property to false.