add startOnRegistryFailure to server.yml to control if start the server after failing to register

[stevehu]

When we set the enableRegistry flag to true in the server.yml to register the service to the Light-controller or Consul for global registry/discovery, the server will stop if the registry is not reachable.

It is the desired behaviour if we are using the global registry for service discovery. However, in the following scenario, we might want the server to start even if it is failed to register.

In a development environment and the Light-control is deployed as a standalone service without the cluster configuration backed by Kafka Streams. The registration is done on a best-effort basis. The purpose of the registry is to monitor the runtime instances with the health check. And to leverage the additional features like server info access and changing the logging level on an individual instance in a cloud environment.

[stevehu]

add startOnRegistryFailure to server.yml to control if start the server after failing to register light-4j master