Move the functional jslib in a dedicated repo

[oleiade]

It has been decided internally to not hold any actual jslib code in the repository itself anymore. As a result, we should move the functional jslib into a dedicated repository.

Thus we should go through the necessary steps to include the functional jslib from its dedicated repo as follows:

• create a dedicated repository for the functional jslib library
• create a build and release for its latest version
• include this version and its build files in the jslib repo
• remove the actual summary code present in the repo

🖖🏻

[oleiade]

Done ✅

There is now a k6-jslib-functional repository 👍🏻