CI: enhancements on the main python script:

  -- at the end of eNB run, eNB log file is retrieved and analyzed for SegFault / Assertions / Real Time issues
     if any found, added to the HTML report
  -- When script fails to retrieve UE IP address, try again and report in HTML report if failed
  -- Core is dumped during seg fault event and added to eNB run log zip artifact

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>