Adding a recovery for displaced muons with low transverse impact parameter

This MR introduces a workaround to recover muons that are produced displaced from the interaction point but have low transverse impact parameter due to their large boost. In this situation the existing LRT muons won't catch those since they are only seeded by LRT tracks and in this situation prompt ID tracks have already reconstructed the muon. At the same time, standard muon combined reconstruction does not catch those since it requires pixel hits in the ID track. Those cases will then be reconstructed separately as an ID track and a standalone muon.

While a proper fix would require a fix in the reconstruction code, discussion with Muon CP and a full data reprocessing, we introduce here a mechanism to tag ID tracks compatible with a standalone muon and create a special muon container to gather those objects. This is needed so that they can use in the displaced vertex reconstruction scheduled in LLP1, and hence this is only introduced for this derivation.

A muon containe merging algorithm had to be also added, since - after asking also the help software list - we realized it was missing. We added that in the same package where other merging algorithms specific to muons are.

Tagging @mamirono , @kbai , @jburzyns , @csebasti , @kdipetri