tauRec: add tau thinning algorithm

Hello,

This MR adds a new tauRec thinning algorithm that will remove all entries from tau-related containers for tau candidates below a minimum tau pt threshold.
The motivation is explained in detail in https://indico.cern.ch/event/986226/contributions/4152506/attachments/2164807/3653366/TauCP_Seeds_LRT_17Dec20.pdf (slide 10).
In R22, we will have to relax the seed jet pt cut (15 GeV) currently applied by default in the reconstruction, as it causes tau reconstruction inefficiency.
Instead, we will have to run the tau reconstruction on all seed jets, and at the end, remove tau candidates below a pt threshold (~10 GeV), in order to keep the tau disk size comparable to what it is now.

The algorithm is added to tauRec but not yet deployed in RecExCommon_topOptions, on purpose. This will be done once we converge on the pt threshold, and the seed jet pt cut will have to be dropped at the same time.

Relevant JIRA ticket: ATLASRECTS-5684

Cheers,
Bertrand