Switch CI pipeline to GitHub Actions

It would be a lot easier to maintain the CI pipeline if it was moved to GitHub Actions. It reduces the complexity of the CI set up and is better understood by the current maintainers. Using Azure requires managing and linking an extra account rather than using the one associated with the project. Using GitHub Actions also makes it easier to perform actions on the repository that require authentication, such as publishing to GitHub Pages.

When we make this change, we should switch the Node.js version from 10 to 16 so we can start upgrading and modernizing the build process...and so the library is actually tested on a supported version of Node.js.