Improved report for each backend.

[JonathanHuot]

Before this change upstream health check module reported statuses of all resolved backends ip addresses for the specified fqdn and rendered each backend into a one or more resolved ip addresses. In this change:

• Change html and json to report cumulative status for each fqdn;
• Fqdn specified backend considered to be up if all of the ip addresses are up;
• Display only upstream name, fqdn and health status. Miss check type, risa and fail count and port fields;