Include refactored Flavour Tagging Package

The Flavour Tagging package has been refactored during the last year, including

• restructured python configuration files
• new feature pipeline object to simplify configuration of similar implementations of tagging algorithms
• some preparations to use XGBoost libraries
• updated ITagger and IBTaggingTool interface to improve communication with TupleToolTagging and store additional tag information in Tagger objects

There are still some BOOST dependencies which can (and will) be dropped, as well as some missing-overrides warning which will be fixed soon (therefore WIP).

As soon as this MR is merged and some Flavour-Tagging manuals are updated, several dev-flavtag-X branches can be removed.

Pinging @bkhanji and @sakar.