Cartridges: Add support for cartridges that are enabled by default via default-sculptor-generator.properties
In chain overrideable module: small fix to not re-fetch properties
Make mongodb support a cartridge (partial).   Moved mongodb templates into a cartridge sub-package.  RootTmplExtension for MongoDB is working.  Only issue is ServiceTmplExtension due to a problem with a lack of a no-args constructor.