HPCC-8770 Show eclserver in Topology/TargetCluster page

The Topology/TargetCluster page shows information about the thor,
eclagent, eclscheduler, but not the eclservers. This fix adds the
eclserver information inside the page.

Signed-off-by: Kevin Wang <kevin.wang@lexisnexis.com>
Merge pull request #4331 from wangkx/h8770

HPCC-8770 Show eclserver in Topology/TargetCluster page

Reviewed-By: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>