Implementation of CbmSourceDigiEvents, reading DigiEvents from archive into the ROOT tree

A FairSource class CbmSourceDigiEvents is implemented, which reads DigiEvents from an archive file resulting from online data processing and provides the events to a ROOT tree for further analysis in the FairRun/FairTask framework.

Tested with run 2391 of 2022 (2391_first20TS.tsa) as tsa archive file.

If possible, the MR should be processed with urgency, since it is required for the current mCBM beam time.

To use the functionality, users should use CbmSourceDigiEvents(const char* fileName) in their run macro, e.g.

  FairSource* source = new CbmSourceDigiEvents(inputFileName);
  run->SetSource(source);

An example macro with a simple inspection task for DigiEvents is provided with macro/run/run_inspect_digievents.C.