Early Phase3 Belle II + Beast II within the IR+FarBeamline (|s|<26m). Geometry payloads for the beam-induced background simulation. It requires some modifications of the Belle II sub-system settings (study). For now, the Beast II system is not present in DB so its geometry is built from the XML file. Tested with the master_2021-06-28 branch. + Modified shielding around Belle II, better geometry implementation + extended cavern walls