Make it possible to get the collection for an object

[tmadlener]

BEGINRELEASENOTES

• Add Frame::get overloads that take a podio generated object handle as argument and return the collection this object belongs to if the collection is known to the Frame.

ENDRELEASENOTES

See the discussion in key4hep/k4FWCore#311 for a rationale of this functionality

The main question at this point is whether the existing getName functionality that takes a collectionID should be deprecated and removed eventually.

[m-fila]

Suggested change

	template <CollectionType CollT>
	const CollT& get(const CollT::value_type& object) const;
	template <CollectionType CollT>
	const CollT& get(const typename CollT::value_type& object) const;

Adding a typename here (and in definition below) shouldn't hurt (although we already value_type to be type in the concept)

[tmadlener]

Interesting that this seems to work without typename for gcc11, but not for gcc13. Fixed.

[m-fila]

Do we want to have this for compatibility with other gets in frame? Otherwise, I think the objects already have typedef to their collection so in principle we could use only the overload returning concrete collection

[tmadlener]

Good catch. I haven't thought about being able to return a typed pointer here. For compatibility I would keep this to return a pointer, i.e. all methods of get that take an explicit collection template argument return a const&, the "un-templated" ones return a const*. Alternatively, we only add this once there is an actual use case for it.