Added new file for Bc -> Jpsi Ds(*)+ X with Ds+ -> pi+ pi- pi+ X

Bo Fangrequested to merge
bfang/Bc2JpsiDsX_decfile into master

Added new file for Bc -> Jpsi Ds(*)+ X, Jpsi -> mu+ mu-, Ds+ -> pi+ pi- pi+ X for hadronic R(Jpsi) analysis.

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