feat: use centralized service images (gitlab.com)

mentioned in commit 8ff40364

mentioned in merge request to-be-continuous/samples/python-on-azure!20 (merged)

mentioned in merge request to-be-continuous/samples/python-library!10 (merged)

mentioned in merge request to-be-continuous/samples/python-helmfile-on-kubernetes!53 (merged)

mentioned in merge request to-be-continuous/samples/python-on-kubernetes!44 (merged)

mentioned in merge request to-be-continuous/samples/golang-cnb-on-kubernetes!50 (merged)

mentioned in merge request to-be-continuous/samples/python-serverless-on-aws!120 (merged)

mentioned in merge request to-be-continuous/samples/php-on-kubernetes!97 (merged)

mentioned in merge request to-be-continuous/samples/golang-on-cloudfoundry!53 (merged)

mentioned in merge request to-be-continuous/samples/angular-on-s3!183 (merged)

mentioned in merge request to-be-continuous/samples/golang-docker-on-aws!76 (merged)

mentioned in merge request to-be-continuous/samples/svelte-on-s3!111 (closed)