<!--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=18782) </details> <!--IssueSummary end--> As part of https://gitlab.com/gitlab-org/gitlab-ce/issues/34163#note_34935716 we need to expose some application configuration trough the API, specifically the `available_repositories`. The `/application/settings` endpoint will include all options that are stored in the DB and can be changed while the application is running. I propose creating a new endpoint `/application/configuration` that exposes the items configured in `gitlab.rb`/`gitlab.yml` but doesn't allow updating any of them. We should then avoid confusion between `repository_storages` configured in `gitlab.yml` which describes all storages used by GitLab, and `repository_storages` in `ApplicationSetting` which describes the storages receiving writes. @pcarranza Suggested renaming `repository_storages` on `ApplicationSetting` to `active_repository_storages`: https://gitlab.com/gitlab-org/gitlab-ce/issues/34163#note_35024107