Run3 File Summary Record

This MR introduces a new File Summary Record implementation for Run3.

A few key aspects of the implementation are:

• leverage on the new Gaudi::Monitoring infrastructure
• simple (JSON) persistent format recorded in the ROOT file as a simple string

These features guarantee that:

• it is trivial to add a new entry to the FSR
• extracting the FSR from a ROOT file is trivial:

  import json
  import ROOT
  f = ROOT.TFile.Open("my_file.root")
  fsr = json.loads(str(f.FileSummaryRecord))

At the moment there is still much work to do (reading, merging, more frameworks info to record, ...), but it's a reasonable proof of concept.

Requires gaudi/Gaudi!1379 (merged) gaudi/Gaudi!1389 (merged) !3830 (merged)

Note: that !3830 (merged) is needed only because without it LHCb does not compile if gaudi/Gaudi!1389 (merged) is applied

References:

• https://its.cern.ch/jira/browse/LBCOMP-58
• https://indico.cern.ch/event/1086171/?note=176068
• https://indico.cern.ch/event/1110473/