Draft: B+->K+J/psi(mumu) MC for muID studies - realistic 2023 + expected 2024 no UT

This new MR supersedes the previous 2023 MC produced in !637 (merged) in two main ways:

1. It is produced in a more realistic scenario, includig the BeamLineOffset as in !872 (merged)
2. It includes many more branches for the particles in the decay that might be useful for offline studies

The MR for 2024 MC is instead based on the expected 2024 data-taking conditions. The reconstruction scripts are based on https://rjhunter-docs.web.cern.ch/tutorials/running_over_expected24_simulation.html . No UT is included in the reconstruction at the moment.