nodered: settings.json sits beside settings.js, which reads it from its own directory

#186 moved settings.js to /data for the image's health check but left
settings.json at /config; settings.js requires ./settings.json, so node-red
crashed at start. Both now mount under /data.

modules/nodered/module.json

@@ -80,7 +80,7 @@
       "volumes": [
         "${dir:data}:/data",
         "${dir:state}/settings.js:/data/settings.js:ro",
-        "${dir:state}/settings.json:/config/settings.json:ro"
+        "${dir:state}/settings.json:/data/settings.json:ro"
       ],
       "restart-on": [
         "settings-code",