Evaluate NNJVT for pt below standard lower bound
Currently a default (NN)JVT value of -1 is assigned to all jets outside the recommended pt validity range (20 GeV < pt < 60 GeV). It would be useful for performance studies in Jet/Etmiss to evaluate the network below the lower bound, using the network parameters corresponding to the lowest bin. So, this MR allocates any jets under the lower bound (i.e. pt < 20 GeV) to the lowest pt bin. This will change the decoration values on such jets, but nobody should be using them anyway (and if they are, the current behavior is worse than what this will do), so there is no impact on any "standard" quantities.
This whole binning structure will be superseded in the next round of recommendations regardless.