Flutter login polish (#973)

* Skip config screen by setting demo site default

* Small copy edits

* Login page polish

mobile/pubspec.yaml

@@ -22,6 +22,7 @@ dependencies:
   uuid: ^4.5.2
   app_links: ^6.4.0
   url_launcher: ^6.2.5
+  flutter_svg: ^2.2.0
 
 dev_dependencies:
   flutter_test:
@@ -33,6 +34,7 @@ flutter:
   uses-material-design: true
   assets:
     - assets/icon/
+    - assets/images/
 
 flutter_launcher_icons:
   android: true