[ANN] AWS SDK extended client to support large payloads

[HoneyryderChuck]

This is a follow up to this issue, which unfortunately took me a long time to come back to. But hey, here it is!

I'd like to share the aws-sdk-extended gem, a sister gem to its java and python counterparts, which enable dealing with SQS and SNS messages which surpass the 256KB message size threshold imposed by the corresponding AWS services.

The SDK team is welcome to merge this into the main ruby SDK gem if it thinks it better serves its customer based.

cc @alextwoods @mullermp @RanVaknin

[richardwang1124]

Hey @HoneyryderChuck, thanks for the update! The team will discuss whether we want to merge this directly into the SDK. Great work on the gem!