subtests.docker_cli: Add detach and interaction test

This pull request implements the https://github.com/autotest/autotest-docker/pull/192 inside the test instead of framework to give it time to stabilize before turning it into framework. I believe that this implementation is cleaner and easier to follow than hybrid implementation from https://github.com/autotest/autotest-docker/pull/194

Kind regards,
Lukáš
Well, the code below the `InteractiveBash` is dependent on `InteractiveAsyncDockerCmd` so I'd have to dup the whole `DockerCmdBase`, `DockerAsyncCmd` and `InteractiveAsyncDockerCmd`. It'd be better to create:
`CmdBase`, `AsyncCmd` and `InteractiveAsyncCmd` and replace only the `self._command` in `DockerXxx` versions...

Anyway for now I believe it's better to override one method, than copy&paste or completely change the `dockercmd.py`.

Additionally how many tests require `DockerCmd`-like object with different executable? Usually you'll use `DockerCmd` directly. Detach test is very special in this.