Dropwizard AWS support

[Patryk Orwat]

Hi,

First of all, thanks for the great project! I've been using Dropwizard for years across several companies and always it was easy and straightforward to use and provide new functionalities.

I'm currently working on AWS platform to deliver solutions and had to write custom code to make use of SQS/SNS/STS/... services. That's something that is provided out of the box in Spring (https://spring.io/projects/spring-cloud-aws) and was thinking about adding a support for it in Dropwizard as well. I can contribute to provide necessary code.

The code would need to:

1. Provide global region selection to be used for developers to build AWS service client
2. Allow generating custom credentials provider that would allow assuming an IAM role
3. Provide a mechanism of SQS queue pooling and message processing - it's need to be quite opinionated piece of code although would try to keep it simple
4. Provide an AWS service client factory that would be able to build clients with proper region (global, service specific or fetch from metadata)

What do you think about that?