Information only widget could be shown in the information tab when specfied in the xml

In the .xml of a filter, one can use information only property to transfer information from the server to the client. However, showing these information requires either to use python or to use a dedicated property widget with some dummy non information property.

Adding an xml way to display these directly in the information tab would be nice, something like :

      <IntVectorProperty command="GetNumberOfDomains"
                         information_only="1"
                         name="NumberOfDomains"
                         panel_visibility="information">
        <SimpleIntInformationHelper />
      </IntVectorProperty>