Adding TruthTauMatcher

Description

Adding the possibility to decorate TruthTaus variables to the matched jets. The matching algorithm works similar to the JetMatcherAlg but does a bit more specific stuff for TruthTaus (using the visible part of the taus for matching):

• The matching is done between the given truth tau collection and the given jet collection (in theory it can be also matched to other IParticle objects)
• The algorithm only matches isolated taus, excluding taus from the decay of b- and c-mesons.
• For matching, the visible part of the tau (after decay) is taken, not the original tau before decay.
• The default variable that is written to the matched reco. jets is classifierParticleOutComeFromTruthTaus, which is described here. It allows the separation in pronginess, as well as if it's a hadronically or leptonically decaying tau.
• The block with the new TruthTauMatcher is added to the GN3_dev.json to enable studies concerning taus.

New MR instead of !791 (closed)

Review checklist:

• CI Passing
• Comments addressed
• Source branch is up to date with target