Generate text file artifacts as part of image build jobs which contains iformation regarding the image and tag built
Related to #942 (closed)
Spin-off from https://gitlab.com/charts/gitlab/merge_requests/699
Make it easy to get a list of images built and pushed in a CNG pipeline, so all of them can be accessed somewhere else. Essentially, at the end of each image build job, create a text file which contains the image name and tag and pass it as an artifact. At the end, add a dummy job that collects all these artifacts and provide them as an artifact of itself.