Merging updates to allow reading of HepMcParticleLink_p2-based containers into 21.0-mc16a

These changes are already part of 21.0 and 21.0-mc16d and are required to allow the reading of HITS/RDOs produced in 22.0.X releases. They should not otherwise alter the output of jobs run in this branch. See ATLASSIM-4811. I have also fixed some deprecation warnings from Gaudi in the packages updated as part of this merge request to make the review process easier.