Commit success/fail notification in Web IDE converted to toast messages

Problem

Currently, the success or fail notification of a commit inside the web IDE is done within the sidebar. This unexpected and not very flexible/extendible.

The toast paradigm gitlab-design#65 (closed) is perfect to resolve this in a consistent, clear and flexible way.

Design

• Implement toast paradigm for commit messages as per gitlab-design#65 (closed) resulting in: