refactor gitlab pipeline to individual scripts

.gitlab-ci.yml

gitlab/build_and_push_docker_image.sh

gitlab/check_version.sh

gitlab/configure_helm.sh

gitlab/deploy_maven_artifact.sh

gitlab/deploy_sbom_to_dependency_track.sh

gitlab/perform_gitops_rollout.sh

gitlab/prepare.sh

gitlab/set_version.py

gitlab/test_build_deploy_helm_chart.sh