Cleanup of obsolete code for Run 3

A merge request with this label is picked up in the lhcb-sanitizers nightly slot.

Label to trigger build in nightly slot

Luminosity-related functionality

Code for evaluating efficiencies using MC, including MC truth matching, linker tables, etc.

release notes classification

Changes to monitoring infrastructure or usage

Fixing the issue or merging the MR requires a change in the DB

Merging this would make the stack incompatible with the latest released Gaudi

Requires update of references

No potential reviewers are available

Waiting for a test to be added in the same or in another project.

release notes classification

Saving and reading information to and from files.