Extracts all R packages contained in the repository directory repo_dir and
writes them to a library directory lib_dir.
Details
The lib_dir directory will be created if it does not already exist.
The strip argument may be used to strip certain directories from packages
installed to the library directory lib_dir. This can be used to reduce the
total library file size by removing directories that are not strictly
necessary for the R package to run, such as directories containing
documentation and vignettes.
