Migrate to aws-sdk-go-v2

[mjlshen]

Description This PR migrates the codebase to aws-sdk-go-v2 by migrating these three main components:

• The DynamoDB registry functionality
• The AWS-SD (Cloud Map) provider
• The AWS (Route53) provider

Which then allowed me to:

• Remove the aws-sdk-go session-based logic and replace it with the aws-sdk-go-v2 config-based https://aws.github.io/aws-sdk-go-v2/docs/migrating/#configuration-loading

My commits are all self-contained to align with those 4 steps, so I'd be happy to split this PR up if that would be preferred.

Fixes #4637

Checklist

• [x] Unit tests updated
• [ ] End user documentation updated