HPCC-10821 Fix roxie job not shown on Activity page

From /Status/Servers tree, the existing code reads jobs of each cluster
using Server/@name=cluster's 'AgentQueue'. That does not work for roxie
cluster since @name=RoxieServer, not =roxie.roxie. This fix uses
Server/@cluster=roxie's 'ClusterProcess' to read roxie jobs.

For the jobs on roxie cluser, the 'ClusterProcess' should also be returned
to indicate where the job is running.

Signed-off-by: Kevin Wang kevin.wang@lexisnexis.com