HPCC-10121 Read correct server setting for accessing archived ECL WU

The existing WsWorkunits service assumes only one sasha server in an
HPCC environment. Its functions of archived WUs (list, restore, etc)
fails to get sasha server setting (IP and port) when multiple sasha
servers exist. In this fix, the code will read esp.xml for the
setting. (A separate subtask is created for adding the setting in the
esp.xml). If no setting is found, the code reads environment
settings of the first sasha server (IP and port).

Signed-off-by: Kevin Wang kevin.wang@lexisnexis.com