in borg 1.x, we used to put a timestamp into the archive name to make
it unique, because borg1 required that.
borg2 does not require unique archive names, but it encourages you
to even use an identical archive name within the same SERIES of archives.
that makes matching (e.g. for prune, but also at other places) much
simpler and borg KNOWS which archives belong to the same series.
\n is automatically converted on write to the platform-dependent os.linesep.
Using os.linesep instead of \n means that on Windows, the line ending becomes "\r\r\n".
Also switches mentions of {LF} to {NL} in code and docs.
export-tar: just msgpack and b64encode all item metadata and
put that into a BORG specific PAX header.
this is *additional* to the standard tar metadata.
import-tar: when detecting the BORG specific PAX header, just get
all metadata from there (and ignore the standard tar
metadata).