perl-libwww: Update to version 6.60 and rename from libwww-perl to perl-libwww

perl-libwww: Update to version 6.60 and rename from libwww-perl to perl-libwww

- Update from 5.803 (2004) to 6.60 (2021)
- Rename lfs and rootfile from libwww-perl to perl-libwww making it consistent  with other
   perl programs that start with perl rather than end with it in the name
- Update of rootfile
- Changelog is too long to include here (~900 lines long)
   The details can be found in the Changes file in the source tarball. Looks like more
   than 200 bugs fixed between the existing and new versions.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Michael Tremer <michael.tremer@ipfire.org>