Makes use of normalized Nuxeo's MANIFEST for OSGI compatibility

We want to put nuxeo under OSGI control. This is the continuation of the work initiated while working on APG-240.

• verify backward compatibility of manifests (done)
• replace eclipse buddy policies by OSGI directives or by solving using the bundle context (todo)
• move nuxeo-build at the correct place (in a new repository) (won't fix)
• provide a dedicated target platform [done]
• makes the tests running in eclipse using the standard eclipse plugin for configuring the test class path (require to extend the plugin) [won't fix]
• manifest cleanup [done]
  • remove version attributes from the export directives,
  • use static values for the required directives (bundle-version ...),
  • pretty print the OSGI manifest
• configure maven for implementing the eclipse PDE layout and move the OSGI manifest at the right places [won't fix]
• define a new distribution of nuxeo based on felix [todo]
• integrate pax runner in the integration chain for testing the OSGI deployment [todo]

Changes are isolated in NXP-5357-osgi-manifests (nuxeo,nuxeo-common,nuxeo-runtime,nuxeo-core,nuxeo-services,nuxeo-features)