Merged requested to merge bcouturi_fix_dd4hep_properties into master
Changed the logic in LHCbApp and DDDBConf so that the following order is used for the properties:
DD4hepSvc, DDDBConf, LHCbApp
With this change it is possible to set in DD4hepSvc a conditions version which will not be overridden by the application.
Furthermore, while reviewing the code, we realized with Marco that the naming conventions in DD4hepSvc were not very consistent, so I harmonized that.