2) add ndbinfo.ndb$config_values table which returns
   the currently configured values for each data node
 - add ndbinfo.config_values view
 - extend ConfigValues with a "by index iterator" allowing
   the configured values to be extracted without knowing
   which keys are actually in the hash. Add unit test for
   this new iterator.
 - add test showing how config_values can be joined with
   config_params to get reports of current values.