Simplify visualization telemetry

[flash1293]

Currently the telemetry for OSS visualizations is using the task manager to run an aggregation job daily collecting telemetry data. As the telemetry service itself makes sure to only run once a day it's not necessary to use the task manager directly anymore - instead, the whole task collecting the data can run directly in the usage collector.

Without task manager the oss_telemetry does not depend on task manager anymore, it can get moved into the visualizations plugin as a service.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[wylieconlon]

@flash1293 At the time this was implemented, the usage collector was being called from a user's browser if needed, and the goal of the usage collectors was to be as fast as possible- this is why the actual aggregation was done separately, and then the results were saved. Has something about this changed so that the usage collector can do more work? This might be a question for members of @elastic/pulse

[Bamieh]

If the task takes too long then caching it every 24 hours makes sense. If it does not take too long then it is OK to fetch usage on the spot. The telemetry is sent at least once every 24 hours and when users click on the example flyout. If lens is only doing ES queries i believe there would be no need to cache the requests.

[flash1293]

@lukeelmers For telemetry of "Visualize visualizations" it looks like it would make sense to move the telemetry into the visualizations plugin. That would imply the app arch team is going to own it (at least temporarily). Do you think that makes sense? The Kibana app team would still take care of migrating it over.

[lukeelmers]

For telemetry of "Visualize visualizations" it looks like it would make sense to move the telemetry into the visualizations plugin.

Agreed, this was a bit of an ambiguous item anyway when we started migration, but as it tracks usage for all of visualizations, the visualizations plugin feels like a sensible place for it.

cc @ppisljar in case he feels otherwise