Waveform reconstruction

Code to reconstruct waveform RDO data into low-level WaveformHit objects.

Also includes reconstruction of the LHC clock via FFT to give good local timing resolution. Also includes xAOD containers and converters to persist this data.

New packages are: Scintillator/ScintRecAlgs Scintillator/ScintRecTools xAOD/xAODFaserWaveform xAOD/xAODFaserWaveformAthenaPool