Draft: Changes to VELO tank and upstream for Run 3
Removed BLS and GValve, added elliptical head of the velo with flanges, added vacuum infrastructure, manifold and pump, moved PipeJunction from BeforeMagnet to VP, extended a little bit VP region into BeforeVelo.
Tested for overlap dumping the DDDB to GDML, reading into ROOT and using the ROOT geometry tools: VP seems to be extruded by VacTank.
Tested with Gauss_v55r1: minor changes needed to Sim/Gauss/options/BeforeVeloGeometry.py and Sim/Gauss/python/Gauss/Configuration.py due to the change in the location of the PipeJunctionBeforeVelo.