Update natural constants to latest PDG values

[renereimann]

The values of natural constants are from PDG 2006 (https://pdg.lbl.gov/2006/reviews/consrpp.pdf) which are outdated and have significant larger uncertainties compared to up-to date from PDG 2021 (https://pdg.lbl.gov/2021/reviews/rpp2020-rev-phys-constants.pdf).
Also in the mean time the SI unit definition has been changed. This would effect:
https://github.com/project8/locust_mc/blob/master/Source/Core/LMCConst.hh
Kassiopeia uses the same constants and should be updated at the same time (otherwise we are inconsisten and partly outdated).
https://github.com/KATRIN-Experiment/Kassiopeia/blob/main/Kommon/Core/Utility/KConst.h

[renereimann]

In Kassiopeia this has been fixed by KATRIN-Experiment/Kassiopeia#55