Change defaults in [AnalysisTimingATLASpix]
Following the feedback from DD about the corry note:
cluster_size_cutnow defaults to -1, i.e. not used (before it was 100)
cluster_charge_cutnow defaults to -1, i.e. not used (before it was 100k)
high_charge_cutnow defaults to
high_tot_cut(which is equivalent if no configuration is available).
This MR should be merged AFTER !198 (merged).