New lines selecting B -> D Pi0/Eta(') decays

[skip ci]

We add lines for the charged modes B+ -> Ds+[->KKpi] Eta(') with Eta(') -> pipigamma(gamma), with pi+pi- and pi+pi+ combinations.

For the wrong-sign lines, we set no prescale as we will need them to retain some events after final offline cuts are applied, to model combinatorial background. We then also remove the prescales of the existing D0Etas lines.

We remove the foreseen B -> D X0 lines (with D=D0[Kpi],Ds+[KKpi] and X0=pi0,eta reconstructed in two photons, one of which converts to a dielectrons) from the title. These will be part of a different merge request (!5376 (merged)) once dielectrons are moved to standard particles by Fionn Bishop.