Migrate to shared haf-app-test-runner image from common-ci-configuration

- Use haf-app-test-runner:feature-haf-app-test-runner (Python 3.14, Poetry, Docker, JMeter)
- Remove docker-ci-runner-build job (no longer needed)
- Remove docker/ci/Dockerfile (using shared image)
- Simplify .hafbe_test_base before_script (docker/compose pre-installed)
- Remove pip install poetry from pattern-test (pre-installed in image)

This eliminates per-project CI image build overhead and provides
consistent test environment across all HAF applications.