Add setup and teardown functions in StepConfig

[acostapazo]

It would be awesome to set setup and teardown variable in each step

What happens if you run this code and the test fails? Now docker-compose down, won't be called.

steps:
  test-e2e-local-inmemory:
      run:
        - docker-compose up -d
        - pytest -m end2end --variables tests/end2end/envs/local.yml
        - docker-compose down
  test-e2e-local-sqlite:
      run:
        - docker-compose up -d
        - pytest -m end2end --variables tests/end2end/envs/local.yml
        - docker-compose down

This behaviour is a pitty, so I propose something like the following:

steps:
  test-e2e-local-inmemory:
      setup: docker-compose up -d
      teardown: docker-compose down
      run: pytest -m end2end --variables tests/end2end/envs/local.yml
   test-e2e-local-sqlite:
      setup: docker-compose up -d
      teardown: docker-compose down
      run: pytest -m end2end --variables tests/end2end/envs/local.yml