Make genie sys stage more generic

[JanWeldert]

The stage can now be used for all cross-section uncertainties that genie provides. It can be specified which ones to use e.g.

[xsec.genie_sys]

calc_mode = events apply_mode = events

interactions = Genie_Ma_QE Genie_Ma_RES Genie_Ma_RES_NC Genie_Ma_COH_PI names = maccqe maccres mancres macohpi

param.Genie_Ma_QE = 0.0 +/- 1.0 param.Genie_Ma_QE.fixed = False param.Genie_Ma_QE.range = nominal + [-2.0, +2.0] param.Genie_MaQE.tex = M{A,QE}

param.Genie_Ma_RES = 0.0 +/- 1.0 param.Genie_Ma_RES.fixed = False param.Genie_Ma_RES.range = nominal + [-2.0, +2.0] param.Genie_MaRES.tex = M{A,res}

param.Genie_Ma_RES_NC = 0.0 +/- 1.0 param.Genie_Ma_RES_NC.fixed = False param.Genie_Ma_RES_NC.range = nominal + [-2.0, +2.0] param.Genie_Ma_RESNC.tex = M{A,res nc}

param.Genie_Ma_COH_PI = 0.0 +/- 1.0 param.Genie_Ma_COH_PI.fixed = False param.Genie_Ma_COH_PI.range = nominal + [-2.0, +2.0] param.Genie_Ma_COHPI.tex = M{A,coh}

[philippeller]

Could you document what exactly needs to be added to PISA cfgs that use the old stage for backward compatibility?

[philippeller]

Ok just realized the defaults are set on L.42-23