2 Factor Authentication for Google Drive, changes:
+ parsing additional page with challenge - pin code verification
+ calling the interaction dialog requesting the code
+ dialog title changed to more general: Authentication Code
+ dialog shows url field only if not empty

Change-Id: Idb3ebbad6a12849b9e50af87b46324bfbe966bab
Reviewed-on: https://gerrit.libreoffice.org/25002Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: David Tardon <dtardon@redhat.com>