GUI front end to CI functionality

Description

Provide a way for GitLab administrators to create/manipulate .gitlab-ci.yml job blocks and select scripts that it calls from within the frontend GUI without having to edit the file directly.

Proposal

Automate creation of .gitlab-ci.yml so users can quickly create, test, re-order, and re-use configurations and job blocks as needed. Allow users to select scripts called by CI from a list of files in a user-defined scripts location in the target repo.

The addition of this functionality has the following advantages:

• Make configuration of GitLab CI more straightforward and easier to use
• Make configuration of GitLab CI evident within the GUI frontend
• Eliminate typos and syntax errors that cause loss of productivity

Implementation considerations:

• This functionality should not interfere with users who choose to create/edit .gitlab-ci.yml by hand

This is proposed as an EE feature/option. It will make CI tools easier to use and will thus help further differentiate EE from CE