Create Web Service action is not present for source model with schema root objects

If a source model is created (import or otherwise) that has only schema or catalog root elements, the Create Web Service action returns isApplicable() == FALSE and does not show up in Modeling menu

Debugging revealed that the modelResource.getEObjects() call was assuming the returned list was ALL the EObjects in the model and it actually only returns the primary "root" EObjects.

Need to add a model visitor to dive into the contents to discover Table and Procedure objects.