Add decay modes to the EvtBcVHad (BC_VHAD) model.

Summary:
Add Bc -> J/psi K+ pi- pi+ pi- pi+, Bc -> J/psi K+ K- pi+ pi- pi+ & Bc -> J/psi 4pi+ 3pi- decay modes to the BC_VHAD model,
courtesy of Aleksei Luchinsky, Anna Danilina, Dmitrii Pereima & Vanya Belyaev (LHCb).

LHCb code review (for Sim09 release) was done last year: https://gitlab.cern.ch/lhcb/Gauss/-/merge_requests/772

Test Plan: Decay model physics reviewed by LHCb: https://gitlab.cern.ch/lhcb/Gauss/-/merge_requests/772

Reviewers: kreps, tlatham

Reviewed By: tlatham

Subscribers: #evtgen_admins

Tags: #evtgen

Differential Revision: https://phab.hepforge.org/D78