Aggregate data regarding rule(set) usage

Is your feature request related to a problem? Please describe.

As tool providers, we don't know how the tool is used, how many people use the published rulesets, which rules are most often disabled, and how the configurable rules are used. When linting, report which rules and rulesets are used (in aggregate, no identifying information).

Describe the solution you'd like

I want to be able to answer the questions:

• which provided rulesets (such as minimal, recommended) are used and how much? We don't have a "none" option but also identify an empty extends array
• which built-in rules are used and at what severity?
• are configurable rules used?

This feature must be disabled when the config/environment variable (see #1044) is set, so that users can easily disable all reporting to us.

Describe alternatives you've considered

We don't currently collect this data, so I considered carrying on without it. But I think the extra context can inform our priorities.

Start by tracing the linting path that loads rulesets and rules, then read the configuration and environment-variable opt-out described in #1044. Define the aggregate data to report for built-in rules, severities, configurable rules, rulesets, and empty extends arrays; done means reporting is non-identifying and fully disabled by that opt-out.