Provide a hint to check the logs if the service does not start

[markwalkom]

I have noticed an increase in users not able to start Elasticsearch after installation, and they are only providing the response from the service start command. Is it possible to have Elasticsearch return a message like "Please check your Elasticsearch logs for more information." to the output to give people a hint on what to do next. I feel that it'd help reduce a lot of friction and give users guidance.

Here's some recent topics where it would have helped;
https://discuss.elastic.co/t/elasticsearch-service-failed-to-start-on-centos/247034/
https://discuss.elastic.co/t/es-7-9-doesnt-start/246908
https://discuss.elastic.co/t/elastic-search-failed-to-start/246845

[elasticmachine]

Pinging @elastic/es-distributed (:Distributed/Allocation)

[elasticmachine]

Pinging @elastic/es-core-infra (:Core/Infra/Core)

[rjernst]

This should be possible. I've marked this for discussion, but I believe this is a trivial change. We just need to write a message with the ES log path to stdout, which will get picked up by journald/systemd.