Draft: FlavourTagging: New inclusive tagger

@mfuehrin @vchobano @wendelj This branch updates Phys/FlavourTagging so that a new inclusive tagger of the type currently being documented in LHCb-PAPER-TBD "Inclusive B-meson flavour tagging algorithm at LHCb" can be implemented. Whether the final model is uploaded in this MR already remains to be seen. More importantly, the DevelopmentTagger is added to the most recent Tuning and allows for TupleProduction for improved model training. This MR implements the following functionality:

• It allows a tagger to reuse tagging decisions of other taggers (this tagger is marked "deferred" and runs last)
• Implements architecture of the new tagger
• Adds development tagger to Tuning and disables it by default
• Adds RestrictedTaggerList GaudiProperty for BTaggingTool to disable taggers except for a few that should run (dev feature)
• Implements three new features in Feature generator (Theta angle, PIDk, PIDp)
• Reordered several #includes in Phys/FlavourTagging and removed global occurrences of "using namespace std"

added Flavour tagging label

added enhancement label

changed title from Draft: FlavourTagging to Draft: FlavourTagging: New inclusive tagger

mentioned in merge request !1115 (merged)

@vjevtic what is this MR? It is in addition of, or instead of, !1115 (merged)?

resolved all threads