libproj_install_proj_data: Download and install PROJ data files
Description
Since PROJ 7.0, the data files used to convert between horizontal and vertical datums
are packaged separately. You can access these files as needed using the PROJ
networking capability (e.g., with libproj_configure(network_enabled = TRUE)) or
you can download them all at once. This function searches for the latest release
from the PROJ-data.