Add an alg to copy b-tagging (float) branches onto the associated jet

Directly reading b-tagging variables from the xAOD::BTagging object and writing these to the output tree will produce non-aligned indices when any thinning is applied to the jet container.

This alg transfers the b-tagging branches from the BTagging to the Jet, so that the selection can be applied to the jets, and then the copied branches saved directly. For the initial implementation, this does only:

• Input: "reco4PFlowJet" collection (matching OR and SYS)
• Branches: GN2v00_p[b,c,u]

If there is any use case, this could be made configurable in more detail. For now it is simply on/off based on flags.Analysis.write_small_R_gn2_branches. The python lives under output/ttree and the CA is merged into minituple_cfg, as this is the only place it is currently applicable. If it is later wanted for h5 output, some rearrangement would be needed.

@smeriano do you want to try this out?