HPCC-10288 - Add RemoveOwnedSubFiles (for 4.2)

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5101 from jakesmith/hpcc-10288-4.2

HPCC-10288 - Add RemoveOwnedSubFiles (for 4.2)

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>