Delete GitLab > Elements sub-section

Rundant: Elements page in Git lab is the same as Content. Index code uses Content. 

https://github.com/t4d-gmbh/ci-cd-workflows/blob/368ef006606b415eb8e7d3f73e7a69f4a0de38b4/source/content/creating_workflows/gitlab_pipelines/elements.md

Sorry, couldn't find how to deleted from the GitHub IDE 😅 probably easier from the terminal