Integration test can optionally consume cluster state as generated by
the call to `osctl cluster create` and use it to discover nodes in
integration tests.
This means that now CLI tests can use that as discovery source, and
API/K8s tests by default as well.
Flat list of nodes is to be replaced by something more complex in the
next iteration, but it's good for this PR.
As a demo, add CLI test with multiple nodes (dmesg).
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>
