add flag to disable the reading of the MDT detector status from DCS
This MR introduces a new flag which toggles the reading of the MDT detector status from DCS. In regular reco jobs the detector status is used in the region selector, the calibration and the hole search. For the reconstruction of the MDT calibration stream the reading of the MDT HV was allocating too much RAM killing the jobs (this is not a problem in regular reco jobs since the events are time ordered, while in the calibration stream they are not). Therefore this option now allows to switch off the reading of the detector status