Update waveform reconstruction

Update the waveform reconstruction to always produce a hit at the nominal trigger time. Add conditions tool to provide the nominal trigger time and the per-channel offsets (due to cable lengths) in the digitizer readout. Updated WaveformHit to add trigger_time data member. Updated Clock reco to provide amplitude and offset in mV. Updated Waveform mapping tool to provide reverse mapping (id -> channel) needed for offsets in MC