MuonGeometry - Another trial to decouple the aligned muon world from the ATLAS world
In !68671 (merged), I attempted to decouple the aligned muon world from ATLAS such that the created GeoModelTree is deleted once the alignment IOV boundaries are crossed. However, that only worked because of a leaking reference count (cf. !68772 (merged)). Once fixed, the system collapsed as the root node of the muon elvery tower was indeed deleted. Let's write the world as a different conditions object with the same IOV boundaries as the detector manager