Stabilize and refactor autotest execution - #334

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, docker/build-push-action@3b5e8027fcad23fda98b2e3ac259d8d67585f671, docker/login-action@f4ef78c080cd8ba55a85445d5b36e214a81df20a, docker/metadata-action@v5. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/