Implement the GET /project/:project_id/articles API endpoint
Retrieve the list of articles for a given project
Same as the GET /projects/:id/repository/tree GitLab API endpoint.
- Use the Gitlab API to retrieve the list of all the files from a repository
- GitLab API doc to list repository tree : https://docs.gitlab.com/ee/api/repositories.html#list-repository-tree
- Filter the GitLab API response to keep only *.md files
- Send that filtered data as a response.