Best practise using companion object containing constants as done for
collectionConfig.
Added new hyperbird.conf configuration to avoid hardcoding hb_init.xml
ELFIN Id and ID_G. Now this information is served to hb-ui by the REST
API: /api/config/ returns JSON like: 
{"config": { 
    "hb_init_ref": { 
      "Id": G20050101000012345
      "ID_G": G10000101010101000
    }
  }
}