Maintain renv lock files for workflows in general?

[genomics-kl]

See here for how a template lock file can be used to 'restore' R libraries in different projects. If we can set this up, then we may be able to 'load' R packages like we do with environment modules currently.

Relatedly, I've started a public (to the BBC) renv cache at /varidata/research/projects/bbc/tools/renv_root/ which can be used to set the RENV_PATHS_ROOT environment variable within a project-specific .Renviron file. This is analogous to our /varidata/research/software/BBC/ folder.