C++ Legacy Cleanup - dynamodb

[meyertst-aws]

Each service will need the following tasks:

• [ ] Update or add Readmes based on current templates
• [ ] Confirm code works as intended
• [ ] Add to SoS and update snippets to current standards
• [ ] Update code comments
• [ ] Fully lint code
• [ ] Delete useless or duplicate code and ensure there are no external links to it
• [ ] Create and/or fix tests as required

[meyertst-aws]

13 Actions and no tests.

[github-actions[bot]]

Marked stale by the Shirriff. Notifying @awsdocs/aws-sdk-docs-code-maintainers