[DOCS] Use JES or Custom Service

[agardnerIT]

This issue functions as a record and decision point for the following question:

Do we custom develop a Keptn service or use functionality available from the Job executor service?

I believe we have discussed this and come to a conclusion that the job executor service will:

1. Provide all functionality we need (ie. running the container + outputting metrics to a backend like Prometheus - via k6 extensions)
2. Be simpler and more future-proof (nothing for the k6-service authors to maintain
3. Be extensible (you bring the container and we'll run it)

That said, the work that has gone into @jainammm understanding and building a sample k6 standalone service for the GSoC project is appreciated, worthwhile and should not be lost.

If I misunderstand the current state, please use this thread to discuss.

Otherwise, please respond with your decision (@jainammm ) of either 1) Use JES from now on or 2) Build a custom service - along with your rationale.

Once this is completed, the second-half of the GSoC work can start.

[jainammm]

As mentioned above by @agardnerIT, we have decided to go with the Job Executor Service for K6 integration. It covers all the requirements.

Commenting on the current state of new service:

1. Has the boilerplate code for the new service
2. Start k6-service in K8s
3. Listens to test.triggered cloudevent
4. Sends test.started cloudevent
5. Sleeps for 5 seconds (Here the logic of test execution will be kept)
6. Sends test.finished cloudevent back
7. Test for handler of these events