Proxy support for AWS SDKs

Is your feature request related to a problem? Please describe.

Data Prepper running behind proxies is not currently supported.

Describe the solution you'd like

Follow the same approach as we are planning #300. Each AWS configuration can include a new proxy configuration.

For example, within peer-forwarder:

  prepper:
    - peer_forwarder:
        discovery_mode: aws_cloud_map
        proxy: http://my-proxy:9000

Describe alternatives you've considered (Optional)

We may wish to have a default AWS configuration available for users to configure. This could be used for any plugin which uses AWS. However, this would be a much larger change.

AWS Components Needing Updating

• peer-forwarder Cloud Map (AWS SDK v2)
• opensearch (AWS SDK v2)
• CloudWatchMeterRegistryProvider (AWS SDK v2)
• ACMCertificateProvider (multiple plugins; AWS SDK v1)
• S3CertificateProvider (multiple plugins; AWS SDK v1)