Provide map style config for release (#321)

And update nightly from the trial version we were using.

element.io/nightly/config.json

@@ -52,5 +52,5 @@
     "features": {
         "feature_spotlight": true
     },
-    "map_style_url": "https://api.maptiler.com/maps/basic/style.json?key=JCdnMQY3oGklTYYLIvtI"
+    "map_style_url": "https://api.maptiler.com/maps/streets/style.json?key=fU3vlMsMn4Jb6dnEIFsx"
 }