Tidying up Truth[Decay]CollectionMaker following migration to R/W/D handles
This MR makes a few refinements to Truth[Decay]CollectionMaker following the migration to R/W/D handles, namely:
- passing event context also to decorators
- header-only declaration/initialisation of properties
- using Gaudi::Properties for all non-handle properties
- initialisation of decoration names with whatever input collection name is provided, to account for the (unlikely) possibility of a truth collection other than
TruthParticles
being required