Update aws-sdk-* gems to v3 and use faraday_middleware-aws-sigv4 gem

What does this MR do?

• Use v3 of aws-sdk. This is backward compatible as per https://aws.amazon.com/blogs/developer/upgrading-from-version-2-to-version-3-of-the-aws-sdk-for-ruby-2/
• Specify aws-sdk-cloudformation in the Gemfile since that is the only one we want. If we continue with aws-sdk, the whole world will be pulled in unnecessarily.
• Use faraday_middleware-aws-sigv4 gem which is the recommended one to be used with v3 of aws-sdk gems instead of faraday_middleware-aws-signers-v4
  • Change service_name to service as mentioned in the readme

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Closes #37931 (closed)