Conditions migration for pixel charge calibration (ATLASRECTS-4565)

This is the last piece of the conditions migration for athenaMT.

The InnerDetector/InDetConditions/PixelConditionsServices/src/PixelCalibSvc.cxx is deleted.

Note that due to the rounding issue (string to float), the result will change from the HITS level. Thus, the reference should be updated once this is merged.

Checking why the threshold values in the conditions DB are so different from old reading scheme to new reading scheme is not simple as done via job option, since there is no test algorithm to dump out the threshold values from the conditions in the old method.

But for instance, see

https://gitlab.cern.ch/atlas/athena/blob/master/InnerDetector/InDetConditions/PixelCoralClientUtils/PixelCoralClientUtils/PixelCalibData.hh#L121

Clearly, the read value is not same as simple reading scheme as we propose in this MR. InnerDetector/InDetConditions/PixelConditionsAlgorithms/src/PixelChargeCalibCondAlg.cxx

The values obtained from the old method seems wrong... We correct it in this MR.