POC: Backoff retries

[nwithan8]

Description

• Built-in backoff retry logic to automatically retry HTTP calls when retrieving specific status codes
  • Credit to the Polly library that handles this, and this thread for figuring out how to do it with RestSharp

Testing

• No unit test currently, since it's hard to simulate a bad status code.
  • If we purposefully include "good" status codes in the list of retry codes (e.g., trick the system into retrying even on a 200), we can see the system works as expected.

Pull Request Type

Please select the option(s) that are relevant to this PR.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Improvement (fixing a typo, updating readme, renaming a variable name, etc)