Add a S3 storage backend that uses the AWS SDK

[gaul]

Similar to Azure in #606 and Nio.2 in #697, using the AWS SDK instead of jclouds might allow better S3 compatibility. Given Apache jclouds will soon move to the attic it will not be possible to further evolve its S3 provider.

Adding an SDK-based storage backend poses challenges since there is a v1 and v2 API. AwsSdkTest currently uses v1 and migrating appears difficult even using the provided OpenRewrite recipe. I am not sure if you can have both the v1 and v2 API exist in the same application so migrating might be a prerequisite.