Replace Rusoto with aws-sdk-rust in tests

[adamjq]

This PR removes Rusoto, which is currently in maintenance mode, from the Integration test examples and replaces it with aws-sdk-rust. The AWS Rust SDK is still in developer preview but is tracking to GA and has more recent active downloads than Rusoto.

Includes:

• removes rusoto in favour of aws-sdk-rust
• refactored integration tests for DynamoDB, SQS and S3 SDK clients
• separated test files for MinIO, ElasticMQ and DynamoDB Local