needed after https://github.com/key4hep/EDM4hep/pull/389

- Set but unused variables and unused variables or declarations
- Deprecated constructor for a Vector3d from a Vector3f from EDM4hep
- Missing override
- Having a space after `operator""` is deprecated

Made sure we actually would write some stuff to the tree if we had hits

Fix mistake introduce in commit #1bb07c7c: the declaration of "CartesianGridXYZ" had been cancelled inadvertently.

Geant4AssemblyVolume: use the same copy ID for the Geant4 Volume as was set in DD4hep geometry construction

    is now set to [-pi,pi] instead of [0,2pi] if phi IDdescriptor field is signed.

the target is now(?) prefixed with Geant4:: otherwise we get a linking error

It doesn't matter because we don't care about the result