The runner model is only a class responsible for storing information
now. Based on the configuration it picks a strategy for the runner
management. The Poseidon strategy is already implemented and tested.
The Docker strategy will follow.
17 tests are always failing, due to changes introduced when adding the
Runner abstraction. To know only these fail, they now get skipped in
order to make it apparent if tests that should not fail do fail in the
pipeline.
