Rebuild a FilesDaf store's root metadata.json index.
Source:R/files_metadata_json.R
pack_files_daf_metadata.RdWrites the DataAxesFormats-compatible metadata.json consolidated index from
the on-disk tree. Use to migrate a store written by an older dafr (which used
metadata.zip) or modified outside dafr, so it can be served over HTTP and
read by DataAxesFormats.jl.