Use Distroless docker images for `.gitlab-ci.yml` templates
<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=27303) </details> <!--IssueSummary end--> ### Problem to solve Deployed Docker images should be as small as possible so they: 1. load quickly 1. take up less storage 1. have less security surface area ### Intended users <!-- Who will use this feature? If known, include any of the following: types of users (e.g. Developer), personas, or specific company roles (e.g. Release Manager). It's okay to write "Unknown" and fill this field in later. Personas can be found at https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/ --> ### Further details <!-- Include use cases, benefits, and/or goals (contributes to our vision?) --> [CI/CD templates](https://gitlab.com/gitlab-org/gitlab-ce/tree/master/lib/gitlab/ci/templates) use fat base images that include a lot of functionality that isn't actually needed by the resulting app. Alpine is a great base image that is smaller, but Google's [Distroless](https://github.com/GoogleContainerTools/distroless) images are even thinner. ### Proposal <!-- How are we going to solve the problem? Try to include the user journey! https://about.gitlab.com/handbook/journeys/#user-journey --> ### Permissions and Security <!-- What permissions are required to perform the described actions? Are they consistent with the existing permissions as documented for users, groups, and projects as appropriate? Is the proposed behavior consistent between the UI, API, and other access methods (e.g. email replies)? --> ### Documentation <!-- See the Feature Change Documentation Workflow https://docs.gitlab.com/ee/development/documentation/feature-change-workflow.html Add all known Documentation Requirements here, per https://docs.gitlab.com/ee/development/documentation/feature-change-workflow.html#documentation-requirements --> ### What does success look like, and how can we measure that? <!-- Define both the success metrics and acceptance criteria. Note that success metrics indicate the desired business outcomes, while acceptance criteria indicate when the solution is working correctly. If there is no way to measure success, link to an issue that will implement a way to measure this. --> ### Links / references <!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION --> *This page may contain information related to upcoming products, features and functionality. It is important to note that the information presented is for informational purposes only, so please do not rely on the information for purchasing or planning purposes. Just like with all projects, the items mentioned on the page are subject to change or delay, and the development, release, and timing of any products, features, or functionality remain at the sole discretion of GitLab Inc.* <!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->
issue