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.
In general, I think it's important to _decouple_ the XML output from the JSON output. There's no real reason to keep the same, especially because having that goal can make backwards compatibility very, very difficult at times. 

So, basically, there are 2 goals: 
- making it very easy for the client to deserialize the json (+1 using a normal ObjectMapper, without extra config)
- backwards compatibility

Backwards compatibility is by far the most important. If 2.x doesn't need extra config to see JAXB anno's (so that we would be using just a non-configured ObjectMapper for 2.x/wildfly), then it sort of makes sense to have the extra config now. 

Of course, the best of both worlds is being able to use a non-configured ObjectMapper for both 1.x and 2.x. But it's also not necessary and only a plus if that's possible.