Nexus convention on the DB parameters

I think that we should also follow the nexus convention for the params in the DB. It means that in this block:

 <group NX_class="NXdetector" groupName="detector01" alias="InstrumentDetector01_name">
         <name NAPItype="NX_CHAR">${InstrumentDetector01_name}</name>
         <preset_time NAPItype="NX_FLOAT" ESRF_description="Desired measuring time">${InstrumentDetector01_presetTime}</preset_time>
         <live_time NAPItype="NX_FLOAT" ESRF_description="Time the detector has been actually measuring (elapsed_time - dead_time)">${InstrumentDetector01_elapsedLiveTime}</live_time>
         <elapsed_time NAPItype="NX_FLOAT" ESRF_description="Time elapsed between start and stop of the measurement">${InstrumentDetector01_elapsedRealTime}</elapsed_time>
         <calibration NAPItype="NX_FLOAT" ESRF_description="For MCA detectors, coefficients a, b, c to compute a scale based on channel number as a + b * x + c * x * x ">${InstrumentDetector01_calibration}</calibration>
         <group NX_class="NXpositioner" groupName="positioners">
            <name NAPItype="NX_CHAR">${InstrumentDetector01Positioners_name}</name>
            <value NAPItype="NX_CHAR">${InstrumentDetector01Positioners_value}</value>
         </group>
         <group NX_class="NXcollection" groupName="rois" ESRF_description="Names and parameters describing the ROIs applied">
            <name NAPItype="NX_CHAR">${InstrumentDetector01Rois_name}</name>
            <value NAPItype="NX_CHAR" ESRF_description="Parameters defining the ROI. Format: R1P1,R1P2 R2P1,R2P2 ... RnP1,RnP2">${InstrumentDetector01Rois_value}</value>
         </group>
      </group>

parameters as InstrumentDetector01_presetTime should be replaced by InstrumentDetector01_preset_time