convert circleci lint job to github actions

[JakeHillion]

convert circleci lint job to github actions

Start the migration from CircleCI to GitHub Actions with migrating the lint job. Used the structure from @robandpdx to setup Nix and use a GitHub key. Restructured the check from nix flake check to nix fmt; git diff --exit-code so we get a full patch again.

Test plan:

• Submitted this PR with a formatting error. CI failed. Submitted without and it passed.

Co-authored-by: Rob Anderson robandpdx@github.com

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c367e7f) 62.70% compared to head (b3f6fb7) 62.70%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #488 +/- ## ======================================= Coverage 62.70% 62.70% ======================================= Files 123 123 Lines 12097 12097 Branches 1970 1970 ======================================= Hits 7586 7586 Misses 3556 3556 Partials 955 955 ```

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