Create periodic metrics report

[tomsaleeba]

We have the Kibana dashboard, but that's not very accessible. If we could have it periodically emailed to a list of people, that would be ideal. Failing that, maybe we could publish it somewhere.

[tomsaleeba]

If we can upgrade to Kibana 6.8 we can get automated PDF report generation that will email the report: https://www.elastic.co/guide/en/kibana/6.8/automating-report-generation.html.

Currently we're on 6.4.2: https://github.com/ternandsparrow/swarm-rest/blob/master/docker-compose.override.yml#L34.

We have an updated docker image available up to v7.8.0: https://hub.docker.com/layers/sebp/elk/780/images/sha256-eeeac1d2919411e167d945046f04274566927002e078b3efbaf59dfcb2c9c300?context=explore.