Adds zone and load-balancer configuration for eureka

[kvmw]

• Set the load-balancer configuration to prefer zone. (instead of default round-robin strategy).
• Sets the zone of the client based on server uri.

And

• Uses the CloudPlatform interface to detect kubernetes platform, instead of relaying on caCert which is not reliable.

[anthonydahanne]

reviewed with @kvmw - need to repair and check internal CI before merging