* Add collector to ui_metric app so that it reports its own telemetry, so app maintainers don't need to update their apps' collectors.
* Remove UI metrics and some collectors from Index Manamgement, ILM, and Rollups.
* Add user_action app with API endpoint for tracking user actions.
* Track 'Create rollup job' action and publish it in the collector.
* Extract fetchUserActions into a generic helper inside of xpack/server/lib.
* Add trackUserRequest helper.
Enabled:
- View/Manage/Create rollup jobs
Disabled:
- Create a rollup index pattern
- Create rollup visualizations
- Add rollup visualizations to dashboards
- View raw rollup documents in Discover
