Added Material class and isVeloClosed to DeVP class

In order to build the whole stack in DD4Hep without any DetDesc dependency, 2 changes had to be made :

• adding a new material class, wrapping DD4hep one into a DetDesc like interface
• extend DeVP with a isVeloClosed method

Part of set of MRs !292 (merged) LHCb!3789 (merged) Lbcom!629 (merged) Rec!3126 (merged) Boole!418 (merged) Allen!1021 (merged) Analysis!922 (merged) Moore!1806 (merged) Moore!1822 (merged) Alignment!316 (merged) Panoptes!186 (merged)