Stack for release of LHCb v39r1p8 to be used by Gauss next Sim09 release

This is a separate stack for LHCb as it needs to be build with cmake while Gauss will need to be built with cmt.

Release checklist (to be filled by the shifter)

• release build validation (to be checked with the MR author)
• RPMs deployment
• CVMFS installation
• web pages update