Add at least minimal CI testing

[terrillmoore]

As people start using this repo more, we need minimal CI testing.

As a bare minimum, CI testing should prove that we can deploy a server without errors.

There may have to be a hack to deal with Lets Encrypt; we won't have a public address on most CI frameworks, unless we use drone.io and test on a dedicated instance.

Perhaps we can do minimal API tests.

As a stretch goal, we'd test the migration and setup scripts.

With Node-RED 1.1 and later, the Admin API can be used to install flows; so we could potentially mock all the data injection, and then use the InfluxDB and grafana APIs to test data recording.