HZN-508: Update WHATSNEW with OpenNMS 17 changes since Aug 11
HZN-508: Update WHATSNEW with OpenNMS 17 changes since Aug 11

Added credits to community member and added major improvements in documentation.

aihua/opennms,aihua/opennms,aihua/opennms,aihua/opennms,aihua/opennms,aihua/opennms,aihua/opennms,aihua/opennms,aihua/opennms