Bring back the red box for errors #3796

Bring back the red box for errors #3796

This use the previous code by resetting the progress to hide
the progress back and then return errors in the FolderErrorMsg
data role of the folder model.

This also remove the unused FolderRemotePath role, remove FolderStatus
in favor of invalidating all roles in dataChanged and make sure
that the SyncRunning role is transfered properly from the SyncResult
to show the warning icon during sync.