Add tests for AWS S3

[onno-vos-dev]

Description

This issue aims to solve AWS S3 testing specifically as it is likely one of the most used modules of aws-erlang.

See the milestone for further details.

Acceptance Criteria

• An aws_s3_SUITE is created which can talk to a real AWS Account and perform certain AWS Requests towards it. Considering we currently support 235 functions in aws_s3, a subset should be selected for testing. The following subset should be considered part of this issue:
  • Creating a Bucket
  • Deleting a bucket
  • Listing of buckets
  • Write an object
  • Write an object using multi-part uploads
  • Delete an object
  • Deleting a list of objects
  • Reading an object
  • Whether or not an object exists (head_object{4,5})
  • Listing of objects