Use config file to specify transform parameters for kgx

[caufieldjh]

As discussed here: biolink/kgx#470
the current KG-Phenio merged graph does not contain the deprecated tags found in its upstream source.

It would appear that kgx supports specifying node properties but only (at least in our case) through a config file, with the filepath passed to kgx's transform function (in transform_config).

This may suggest that a config file is the most appropriate way to detail transform parameters anyway. That's already how the merge parameters for this and most other KG-Hub graphs are specified.