First round in dropping usage of GaudiAlgorithm in the Packers
Goes together with Rec!2514 (merged), Boole!357 (merged), Gauss!763 (merged), Brunel!1166 (merged), Phys!978 (merged), Analysis!812 (merged), DaVinci!571 (merged), Noether!15 (merged) and Moore!968 (merged)
This includes a major modernization of a good part of the packer code (not all yet), including using functional algorithms and DataHandles when possible.
Edited by Sebastien Ponce