Create Pipeline functional tests

[skonefal]

We have tested most of our components using unit tests, but we need to make sure that our pipelines produce results.

We few tests to check if Estimator returns slack when:

• No executors are on machine
• 3 PR executors on machnie
• 3 PR executors on machne + some revocable executors
• 3 PR executors on machine, but two of them are very recently started
• 3 PR executors on machine, but two of them are very recently started + revocables

And for QoS Controller:

• No executors are on machine
• 3 PR executors on machnie, no IPC drop
• 3 PR executors on machnie, IPC drop
• 3 PR executors on machnie, revocable executors, no IPC drop
• 3 PR executors on machnie, revocable executors, IPC drop, expected some revocations