Adding ProbNNs for Downstream, Upstream and ProbNNghost

Goes with Rec!3926 (merged) and lhcb-datapkg/ParamFiles!99 (merged)

Downstream has essentially same PID inputs as Long, even for RICH1. Only for electrons the frequency is slightly different for brem emission (depends strongly on origin of the track). In the end it was chosen to keep the same models and training.

For upstream tracks PID is almost completely dominated by RICH, to have a smooth response it is therefore strongly advised to cut on having used RICH1 gas (RICH1_GAS_USED functor)