PID module for event reconstuction

The merge request introduces a new data object, cbm::PidParamContainer, which contains PID info, collected from the data, obtained in event reconstruction. Currently, it contains the energy loss values of each track in STS and a place-holder for TOF m2 values. The routine runs after the event reconstruction.

The PID input parameters are stored in individual data objects for each detector subsystem (or, combinations of the detector subsystems in the next iteration) in parallel vectors to the track arrays inside the cbm::PidParamContainer class. If the particular PID input was not produced, the corresponding vector is empty. Otherwise, the the vector is filled with the default values at first, and, if it is possible, the correct PidParam object is created for a given track. For each PidParam object, the method IsDefined() shows, if the particular PID parameter object was created for a given track.

To calculate the energy loss of a track in STS, charges of front and back clusters are stored in the STS hit in single precision.