Add Cloud Tracing payload request/response support

[enricop89]

What does this PR do?

This PR adds the support for the AWS Cloud Payload tagging: https://docs.datadoghq.com/tracing/guide/aws_payload_tagging/#overview. The env variables added are:

1. captureCloudRequestPayload
2. captureCloudResponsePayload

Motivation

Customers able to use these new options + feature parity

Testing Guidelines

I tested using a local repo and trying different inputs

Additional Notes

Types of changes

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

Check all that apply

• [x ] This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• [x ] This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• [x ] 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

[lym953]

Leaving to Cloud Tracing team for another review

[jhgilbert]

Approved with a minor suggestion, along with the typos flagged by another reviewer. Thank you!