This PR adds all the diboson decay channels, including the VV parent processes.
Open questions:
should we always be consistent in the order of listing VV decay products (leptons, then neutrinos, then quarks)? This would also be more consistent with DAS conventions
example: VV->lnu2q instead of VV -> qqlnu (as it currently is for Higgs + HH(bbVV))
This PR adds all the diboson decay channels, including the VV parent processes.
Open questions: