TEIIDDES-2168
* Added validation to detect missing vdbBuilder command in .project
* Added quick fix/resolution to add the entry to the .project
TEIIDDES-2120: Addresses shortcomings of adding imported xsd files

* Closes loopholes with addition of xsd files to a Vdb in the VdbEditor

* VdbUtil
 * canAddModelToVdb checks for duplicate models already in Vdb. However,
   the model resource references includes Xsd files which although are
   resources are included in the 'Other Files' section and a model can
   have the same name as an Xsd file.

* Vdb
 * Avoids further loopholes by making a single addEntry method which both
   model and file entries are added through. Consequently, only one
   function path to determine how the given resource should be added.

* NewVdbWizard
 * Stop Xsd files from being displayed in the Add Models chooser dialog