HuggingFace Rate Limit Improvements

[jlarson4]

Description

• Set CI to cancel concurrent runs – Repeated pushes to the same branch will cancel previous CI runs, and only run on the most recent commit
• Set CI to retry failed HuggingFace requests up to 3 times after waiting a variable amount of time
• Added HF token reference and reference to my maintainer status to the main README
• Added documentation to the docs that details our different ENV vars explicitly
• Added additional test fixtures that allow us to reuse HuggingFace models repeatedly in our tests in location where we are not mutating the state. This allows us to more easily avoid the rate limit

Fixes #1291

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have not rewritten tests relating to key interfaces which would affect backward compatibility