[k6] Refactoring k6 tests (#1)

This commit moves all common request logic into a common folder.
It is needed to avoid duplication before adding JVM warmup phase.

- move registration-related code into common folder
- move passthrough operations into common folder

Issue-ID: CPS-2208
Signed-off-by: danielhanrahan <daniel.hanrahan@est.tech>
Change-Id: Ia9ebf61d21044b43063bde153f9c526e67d607c8
15 files changed