CDK CLI Telemetry

## Description

The CDK CLI team currently has no visibility into how the CLI is performing for users. In order to detect accidental regressions more quickly, and make data-driven decisions on what to work on next, the CDK CLI will begin to collect anonymous telemetry on user commands.

## Roles

| Role | User
|---------------------|------------------------------
| Proposed by | @kaizencc
| Author(s) | @kaizencc
| API Bar Raiser | @iliapolo
| Stakeholders | @rix0rrr @mrgrain

> See [RFC Process](https://github.com/aws/aws-cdk-rfcs#rfc-process) for details

## Workflow

- [x] Tracking issue created (label: `status/proposed`)
- [x] API bar raiser assigned (ping us at [#aws-cdk-rfcs](https://cdk-dev.slack.com/archives/C025ZFGMUCD) if needed)
- [x] Kick off meeting
- [x] RFC pull request submitted (label: `status/review`)
- [x] Community reach out (via Slack and/or Twitter)
- [x] API signed-off (label `status/api-approved` applied to pull request)
- [x] Final comments period (label: `status/final-comments-period`)
- [x] Approved and merged (label: `status/approved`)
- [x] Execution plan submitted (label: `status/planning`)
- [x] Plan approved and merged (label: `status/implementing`)
- [x] Implementation complete (label: `status/done`)

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> Author is responsible to progress the RFC according to this checklist, and
apply the relevant labels to this issue so that the RFC table in README gets
updated.