Merge create sct-runner and provision step

[soyacz]

We could speed up starting the test by merging create sct-runner and provision step to one doing all in parallel. Benefits:

1. speed up by ~1 minute
2. fallback to next availability zone could also fallback sct-runner - saving some costs on cross-az logs transport

Cons:

1. We might lose logs from initial part of nodes setup (or just spend time figuring out how to send it later to sct-runner)
2. GCE/k8s don't support provision step anyway

[fruch]

isn't this kind of the same think as https://github.com/scylladb/scylla-cluster-tests/issues/7398 but with more reaosns ?

[soyacz]

isn't this kind of the same think as #7398 but with more reaosns ?

kind of - more like one way of making it possible