Update the configuration of the FastTimerService used for Offline DQM

  - read the default configuration for the Service and Cliebnt from the
    _cfi files, instead of defining the modules from scracth
  - add a module to set the event luminosity
move the dqmFastTimerServiceLuminosity in the default DQMOffline sequence
Merge pull request #4308 from deguio/DQMFastTimerService_72

Update the configuration of the FastTimerService used for Offline DQM: same as #4307