HPCC-8869 Refactor ECLWatch activity code

This fix made 3 major changes inside CWsSMCEx::onAcivity(): a. move
the existing code for super users (displaying Banner and/or Chat)
into two new methods (no change for process logic); b. move
the existing code for reading/setting workunits on clusters and
servers into a new method. This method will only be called when
client version is less than this version (1.16); c. from this
version, five new methods will be called to read/set workunits on
clusters and servers. 2 Minor changes: a. collect and display better 
information about clusters and workunits; b. collect and display WUs on 
the servers (ECL Server and ECL Agent) which do not belong to any
target cluster.