ci: fix pipeline configuration to let community contributors submit merge requests
Since MRs don't have access to the container registry (of this repo), the images are not pushed on fork (before_script
and after_script
are skipped).
test jobs can't retrieve the image from the registry so they have been merged with their build job which now builds the image and runs the test commands.
Note: due the images not being shared between jobs modification to the base image are not reflected when building other images (--build-arg BASE_VERSION="$CI_COMMIT_SHA"
is no longer passed to the docker command)
Closes #17 (closed)