Use GitHub Apps for workflow authentication

[jpower432]

Issue description / feature objectives

Currently, user dependent authentication is used in GitHub Actions workflows. Using GitHub App would offer a future-proof, scalable way to authenticate in the repository.

Rationale

• A GitHup App acts independently of a user, meaning if the user no longer has resource access it does not cause breakage
• GitHub App tokens support fine-grained, short-lived tokens
• GitHub Apps have a higher API rate limit than PATs

Caveats / Assumptions

None

Completion Criteria

• Create a GitHub App that has proper access to fulfill our workflow needs
• Update workflows to generate and revoke tokens

Resources

• https://docs.github.com/en/apps/creating-github-apps/about-creating-github-apps/about-creating-github-apps