LArHVCorr with offline hash

Thanks to callgrind I found that for the HV-Scale correction we convert many times between online and offline identifier and identifier-hashes. The recomputed HV-Scale correction is internally stored in a vector indexed by offline hash and the offline hash is anyway known by the client, so the conversion is not necessary.

This MR adds an accessor with offline-hash identifier to the LArHVCorr conditions data object and CaloNoiseCondAlg to use this new feature. This implies that the CaloNoiseCondAlg now uses the LArHVCorr object directly instead of the abstract interface ILArHVScaleCorr. But for the noise-rescaling, this is anyway the only implementation that makes sense.