Boilerplate setup - Githubissues

Set up the boilerplate code around the Keptn Argo REST client.

API set up with a sample endpoint
~basic documentation written with code snippets for the different ConfigMaps that need to be set up in ArgoCD~ done in https://github.com/keptn/lifecycle-toolkit/issues/3674
dockerfile added and folder for it added to the various matrices in the pipelines so that the container images are built and pushed to GHCR
unit tests already added to the pipeline with the correct folder name so that everything already gets tested when the code is there

keptn / lifecycle-toolkit