HPCC-11637 Avoid multiple concourrent ECLWatch onActivity queries

Use getActivityInfo() to collect activity info into a cache. Reuse
cached info to set concurrent onActivity queries. The cache time
is configurable (default to 10 seconds).

The code merged from 5.0: Upgrade code to display HPCC server even
if there is no workunit on the server. A user may pause or resume
the server. Collect network address and port info for identifying
ECLCCServer, etc.

Signed-off-by: wangkx <kevin.wang@lexisnexis.com>
I'm still not 100% sure about this change.  
- Has it been added because openWorkunit is no longer checking?  Or is it a completely new test?
- Does this require new access controls to be set up, or is it checking ones that are checked elsewhere?