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>
Vaguely related....   if lo = "W20140101" hi = "W20140101" i.e. the same then this will set mask to

"W20140101" with no trailing *.  I think that is probably a bug - it should always have a "*" appended