PROV-875 Some display-related improvements in ConfigurationExporter

1) Now export display settings as well
2) Now properly insert labels as preferred. Previously is_preferred
would be 0 for display labels created via Installer which meant they
would never show up under Manage > My displays.
3) Wrap display settings in CDATA instead of escaping. This helps with
readability and editing of complex exported displays. A lot.