backups/.rsync_ignore: replaced with .rsync_filter.upload to allow uploading new backups but not deleting existing backups if they don't exist on the local (rsync-invoking) side; and .rsync_filter.download to avoid downloading backups to the local side. this allows storing older backups just on jupiter, where there is much more disk space. note that this change must be made on the remote side (jupiter) for it to be effective, because these are remote-side rules and are only processed by the remote-side rsync instance.