Kie server: add war assemblies and move integ. tests into own module

@etirelli @mrietveld please review the changes and let me know if there is anything I could fix/enhance.
If possible, I'd rather that we don't use the JacksonAnnotationIntrospector or any configuration to the ObjectMapper. In my experience, it ends up leading to problems because users (including QA) on the client side expect to be able to use a unconfigured ObjectMapper to deserialize the class instance.