[bbyy] configurable non-resonant BDT and VBF variable options

The purpose of this MR is to make running the non-resonant bbyy BDT optional, and performing any sort of VBF algorithm optional (including the saving of VBF variables), for flexibility for the user. e.g. for SH(bbyy), neither of these are necessary, and only add unnecessary computation and ntuple branches.

I tested this with the following commands:

bbyy-ntupler /eos/user/a/atishelm/ntuples/SHbbyy/examples/mc20_13TeV.800904.Py8EG_A14NNPDF23LO_XHS_X170_S030_HyySbb.deriv.DAOD_PHYS.e8531_a907_r14859_p6026/DAOD_PHYS.37663611._000002.pool.root.1 --run-config bbyyAnalysis/RunConfig-Resonant-Default.yaml  --out-file analysis-variables-SHbbyy-resconfig.root --e 1000

Output does not contain BDT or VBF branches, as desired.

bbyy-ntupler /eos/user/a/atishelm/ntuples/SHbbyy/examples/mc20_13TeV.800904.Py8EG_A14NNPDF23LO_XHS_X170_S030_HyySbb.deriv.DAOD_PHYS.e8531_a907_r14859_p6026/DAOD_PHYS.37663611._000002.pool.root.1 --run-config bbyyAnalysis/RunConfig-bbyy-skimming-legacy.yaml  --out-file analysis-variables-SHbbyy.root --e 1000

Output contains BDT and VBF branches, as desired.

Later tested all of these cases:

VBFjetsMethod	do_nonresonant_BDTs	save_VBF_vars	result
mjj	false	false	no BDT and VBF variables stored
mjj	false	true	VBF variables stored
mjj	true	false	BDT vars stored
mjj	true	true	BDT and VBF vars stored
BDT	false	false	does not crash, as expected
BDT	false	true	ERROR caught properly during initialize
BDT	true	false	BDT vars stored
BDT	true	true	BDT and VBF vars stored

Where do_GNN2bjetSelection was always false. I think that variable should be fine, because when it's turned on, it still has checks in place for VBF (in the initialize) and BDTs.