HPCC-8897 Pass cacheHint to use paged cache when querying workunits

Workunit/Dali implements a paged caching mechanism for sorted workunits
and dfu workunit results. To use the caching mechanism, this fix passes
cacheHint as parameter when calling getWorkunitSorted(). The cacheHint
is generated based on the hash value of ESP IP/name/startup time. It
is increated by 1 every time when it is used.

Signed-off-by: Kevin Wang <kevin.wang@lexisnexis.com>