feat: opt-in enablement of the instrumentation telemetry client

[Julio-Guerra]

What does this PR do?

Enable the telemetry client when DD_INSTRUMENTATION_TELEMETRY_ENABLED=true

Motivation

AppSec Open-Source Software Vulnerability Scanning (aka ASM OSS Vulns) works on top of telemetry data sent by the tracing libraries. We are launching our beta for AWS Lambda using this short-term solution, but the mid-term one is to leverage a side-scanning agent instead, not requiring instrumentation telemetry at all, and out of the lambdas and tracers.

Testing Guidelines

Additional Notes

Jira: APPSEC-11434

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR passes the integration tests (ask a Datadog member to run the tests)

[Julio-Guerra]

FTR, I just did an e2e test which worked:

1. The telemetry client starts
2. The dependency list is sent
3. ASM OSS Vulnerabilities scanning works and detects known CVEs.