HPCC-11958 Add Roxie State check to preflight

The similar logic in ecl-roxie is used by this fix to
retrieve and format information about roxie state (hash).
The information is displayed inside ECLwatch preflight
page (a new column 'Roxie State'). WsMachine thread pool
is used to improve the performance of retrieving the
information.

Signed-off-by: wangkx <kevin.wang@lexisnexis.com>
You are correct. The context can be removed from this class since it is not used in getRoxieStateInfo().