Add telemetry for Platform

Questions we'd like to answer:

What caused Kibana to crash? How often is it crashing? (frontend & backend)
How frequently are Core APIs used?
Are dry-run migrations being used?
Are new logging features being used? (context-specific files outputs, log rotation)
What UiSettings are overriden in the kibana.yml file or set in the UI? (could indicate we need better defaults)
How many deployments use Kibana in an iframe?
How fast does Kibana load in the browser?
- Probably many other related performance questions
How many SavedObjects do we have?
Configuration based questions (https://github.com/elastic/kibana/issues/56762):
- Which plugins were disabled by the user?
- Are any 3rd party plugins installed? Which ones?
- How many deployments use Elasticsearch node sniffing?

elastic / kibana