infrasys: update to AWS SDK Rust

[jpculp]

Issue number:

#1968

Description of changes:

Replaces rusoto with aws-sdk-for-rust in infrasys.

Testing done:

Coming soon!

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[jpculp]

Opening draft on @rpkelly's behalf. We'll want to merge around the same time that we transition pubsys.