Added resources, filters, request scope, clarity in naming

Added the following resource layers: Catalog, Category. Added normalized
filter support for Listing, Catalog, Category (DtoFilters). Changed
model objects pertaining to request objects to be request scoped rather
than unmanaged. Updated documentation in accords to how to build native
images and setup. Fixed POM file references blocking native-image build.

Change-Id: Id0c0fbced337f0b1b687d2ff2655a38c06b18807
Signed-off-by: Martin Lowe <martin.lowe@eclipse-foundation.org>