HPCC-11775 Improve efficiency of WUiterate in Sasha

WUiterate which scans and filters archives and online workunits,
accessed Dali in an inefficient way, especially in the case of
requesting a single workunit.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
So that would still fail to match

W20140101-020304-1
W20140101-020304-2
etc.