Migrate to GitHub Actions for CI

[danielmmetz]

Goal: get the CI integration up and running again. Progress: Got the unit and lint tests passing. Incomplete and putting out of scope: integration test and release functionality.

• the integration test stalled at the 20m and eventually timed out. I'm leaving it in, albeit commented out, to make it easier for the next attempter given it does actually run.
• the release I'm leaving out entirely as I don't intend to make a new release, I just want to make enough progress to have tests execute for https://github.com/lyft/flinkk8soperator/pull/258

Motivation: Upgrade kubenetes artifacts to handle version 1.22.