ModelCataloguePlugin #102 return only finalized published elements from the queries

after hours of struggling wih features such as PreQueryEvent and hibernate-filters plugin I've just created simple service for list and count desired elements
Merge remote-tracking branch 'origin/develop' into develop

Conflicts:
	ModelCatalogueCorePlugin/test/integration/org/modelcatalogue/core/DataElementControllerIntegrationSpec.groovy
	ModelCatalogueCorePlugin/test/integration/org/modelcatalogue/core/DataElementISpec.groovy