Need to replace the "XML Schema to Relational Source Model" importer by:

1) Adding an "XML Schema (.xsd)" definition to Designer's XML File connection profile
2) In the XML File importer, expose an option to use either an XML File OR an XML Schema for the columns of the generated view table
3) Need to address the use-case where a user does NOT have an XML File and only a schema

• cannot run Preview Data Action
• cannot add to a VDB and perform Execute VDB

NOTE: we can leverage a lot of work done in the WSDL Importer that already deals with exposing Schema to user in order to define result set columns