E2E testing

This doc gives short instructions how to run e2e tests. For the developing e2e tests, please refer to Developing E2E tests.

Prerequisites

Make sure that make and go are available
Make sure that 'docker run' works without sudo, you can check it with
```
docker run hello-world
```

Run e2e tests with

make test-e2e

After a finished test, cleanup is performed automatically. If the test setup failed or the test was interrupted, you can perform cleanup manually:

make clean -C /opt/metal3-dev-env/metal3-dev-env/ && sudo rm -rf /opt/metal3-dev-env/