feat(logging): make elastic stack optional

[viv-4]

The issue of logspout using large amounts of cpu was caused by the source container restarting which is now resolved, 8f1ef39

Still, as these containers are not usually needed they have been removed from the default docker-compose.yml to be added in by install when ENABLE_ELASTIC_STACK=true in .env

[w-le]

Thanks lgtm,
non-urgently, can you also add a convenience improvement where the elastic stack can be installed when a COMMAND LINE PARAM is specified, not just a change in.env? You should be able to copy the method used in ./install:33-37

[caspiano]

Closes #7

[kimburgess]

Not sure if the gelf version supports this, but if this can be filtered to only PlaceOS containers it will protected against trawling all logs.

[caspiano]

Made a bunch of changes.

Fixed

• Ensure all images use dockerhub image host
• Enabling kibana by environment works now

Added

• Adds dependency between the logstash and logstash config validator

Changed

• kibana uses the open distro for elasticsearch kibana
• elasticsearch uses the open distro for elasticsearch
• Use an alpine image for logstash

Removed

• start-services and scripts related to elasticsearch docker-compose files

[caspiano]

Since we're now using the Open Distro for Elasticsearch containers, this issue is not blocked #69

[caspiano]

Also looks like logstash and logspout fail to hit elastic

[caspiano]

Open distro for elasticsearch is SUPER heavy.
Each image is around 1.x GB in size, so we should try to resolve this to decrease spin-up time.

To reduce the size of the images, we can use the open distro plugins on top of blacktop’s alpine kibana/elastic container.

• Plug-ins for Kibana
• Plug-ins for Elasticsearch

Stale review

[caspiano]

What's left of this PR's move to add opendistro for elasticsearch has been shifted to a separate PR, #100