Koding and GitLab integration followup

Moved to https://gitlab.com/gitlab-org/gitlab-ce/issues/22923

Right now we have project settings and application settings for Koding. We should scrap the project settings and have everything under application settings at https://gitlab.com/admin/application_settings It should also have a link on how to install Koding. Basically users have an option to install Koding and Gitlab on the same box or different boxes, with or without Kubernetes (scalable) backend. For time being GitLab and Koding will not be packaged together.

The only thing a user needs to do is add a koding.yml file to their project.

Gokmen and Cihangir and working on this from Koding's side. Devrim thinks no changes are needed at GitLab's side except removing the project settings. For this and other changes in GitLab that needed Koding can probably can make merge request. Otherwise they will contact @eliran.mesika to assign an engineer.

Doing the Kubernetes terminal in GitLab https://gitlab.com/gitlab-org/gitlab-ce/issues/22864 is a separate project that will proceed in parallel.