Updating how LCG layers are introduced
This MR is an updated version of !17 (closed) and follows changes in lhcb/Gauss!635 (merged) and lhcb/Gauss!667 (merged). It is also related with #4.
This introduces LCG_97a_LHCB_5 for Gaussino. As pointed out by @rmatev in https://its.cern.ch/jira/browse/LBCORE-1995 there are two different versions of DD4hep in LCG_97a and LCG_97a_LHCB_4. Moreover, it looks like DD4hep & LCIO are not even in available in /cvmfs/lhcb.cern.ch/lib/lcg/releases/LCG_97a_LHCB_4. As of LCG_97a_LHCB_5, only LCIO is missing. This has to be fixed before we can proceed with this MR.
I introduced a dirty fix that verifies the rest. Still a work in progress.
Edited by Michal Mazurek