[POC][WIP] PIM-3277: introduce PimResourceBundle

The goal of this PR is to introduce the PimResourceBundle which will help us to dispatch normalized events on every create/update/delete. 

TODO:
 - [x] introduce the PimResourceBundle
 - [ ] discuss about the namespaces (inside or outside the PIM ? maybe too early to put it outside)
 - [ ] discuss about moving the SmartManagerRegistry inside this bundle
 - [ ] provide a simple example on one of our bundle or controller/manager
 - [ ] specs
 - [ ] doc

![unnamed](https://cloud.githubusercontent.com/assets/3691804/4736502/f80b6088-59ec-11e4-9009-69f3934b9f02.gif)

Agree from open/close point of view. A bit worried about the current detach/clear manipulation we do on the UOW. We perhaps need to flush explicitely the entities (resources)