Dedicated ChatOps Interface

ChatOps is a large enough feature that it should have its own place in the GitLab UI, rather than being stuck in the pipeine/job view.

The goals of this interface would be to have:

• Easy to understand audit log of who triggered a job, what the parameters were, if it was successful or not, and finally a link to the job. This would include in-progress jobs.
• A method to invoke a ChatOps job through the UI, without having to switch into the chat client.
• An option to take you to the ChatOps settings, to control the options like job permissions.

It probably makes the most sense for this to live within the CI/CD main menu item.