Add rclone support

[davidmeiser-progenity]

rclone has syntax similar to rsync and can be used to copy files to or from public cloud providers. Unlike rsync, when passing file lists using the "--files-from" option, rclone requires output like "/dir1/dir2/**". The behavior is similar to the "--robocopy" output of qsplit. It would be awesome if the required rclone behavior was included in qsplit.