HPCC-9126 DFU Workunits Refactor

Fixes HPCC-9126

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
HPCC-9121 Add Wuid filter by field to filter by
Fixes HPCC-9121

Signed-off-by: Miguel Vazquez <miguel.vazquez@lexisnexis.com>