Add RTA/2023.12.07 stack

Stack to be used for HLT2 PbPb processing. See main relevant MRs under https://gitlab.cern.ch/groups/lhcb/-/milestones/12#tab-merge-requests

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