feat: add webpack publish to gitlab pages job
Adds a new job webpack-publish which compiles a webpack bundle and puts the public folder in artifacts.
Projects will most likely need to override the script
part to match their project structure. An important step is having the built website in the public folder at the project's root. See the GitLab's documentation.
This job will only run on a push to the default branch, and only if build, test and lint have been successful.