## Description
Instead of initializing static AWS credentials, we rely on the
credential provider chain in [Kopia](https://github.com/kopia/kopia/pull/2213) to discover and initialize credentials.
This currently supports the following in this order:
- Static credentials
- Environment variables (what Corso used to implement)
- IAM
Going forward, this will also allow us to support shared credentials (cred file) once that is
added to the credential provider chain.
## Type of change
Please check the type of change your PR introduces:
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 🐹 Trivial/Minor
## Issue(s)
- #384
## Test Plan
<!-- How will this be tested prior to merging.-->
- [x] 💪 Manual (see test output below)
- [ ] ⚡ Unit test
- [x] 💚 E2E
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