Document how to verify an Enterprise cluster is correctly configured

Once a user has finished [setting up](https://docs.influxdata.com/enterprise_influxdb/v1.8/install-and-deploy/production_installation/) an Enterprise cluster, they often want to verify they completed all steps and the cluster is configured correctly. A cluster verification document would be very helpful. Some topics it should explain:

- How to confirm all meta and data nodes are connected to the same cluster.
- Simple tests to ensure data replication works between nodes.
- Endpoints to ping and expected responses to confirm availability.
- How to confirm security is correctly enabled (authentication and HTTPS).
- Expected log lines during startup to identify errors or misconfiguration.

##### Relevant URLs
https://docs.influxdata.com/enterprise_influxdb/v1.8/install-and-deploy/production_installation/

##### What products and version are you using?

InfluxDB Enterprise 1.x