Add 'run once' logic for setup / teardown

[yorugac]

Feature Description

It is mentioned in k6 docs that k6 runs setup and teardown functions only once per test. While this specific page does not mention k6 Cloud test runs, they use the same logic: no matter how many instances were involved in a test, setup and teardown run only once, in some one instance.

To be consistent with k6 Cloud test runs, k6-operator should have the same logic of running these two functions only one runner, with all the accompanying logic (like passing data returned from setup).

Suggested Solution (optional)

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Already existing or connected issues / PRs (optional)

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[cmergenthaler]

Any plans on implementing this yet? We are really interested in a once-executed setup/teardown :)

[na--]

Just to be thorough, I've explained my proposal for native distributed execution in k6 (see grafana/k6#3218 and grafana/k6#3217). It's not meant to replace k6-operator, but rather to make k6-operator easier to develop and focused only on the k8s specifics, not the actual distributed execution of k6 tests and on re-implementing things that already exist in k6 like setup() and teardown() handling.

One of the firsts steps in that chain of PRs (grafana/k6#3205) actually delivers this, albeit in a currently untested and non-error-handled kind of way... 😅 Still, the important part is that distributed metrics handling (grafana/k6#3213) is not actually needed for setup() and teardown(), so it might be easier to work on polishing grafana/k6#3205 (with tests and error handling) and migrate to the new distributed execution instead of re-implementing support for managing setup() and teardown() externally again.