Determine how to replace Bootstrap popover with GitLab UI popover in HAML files

There isn’t a clear approach to adopting GitLab UI popover component in places where HAML data-popover component is used. Let’s use this issue to discuss alternatives.

• app/views/projects/pipelines/_info.html.haml
• app/views/projects/merge_requests/show.html.haml
• app/views/projects/commit/_signature_badge.html.haml
• app/views/projects/blob/new.html.haml
• app/views/projects/blob/_editor.html.haml
• app/views/layouts/nav/sidebar/_project.html.haml

Implementation Strategy

1. Implementation for new GitLab UI helper
2. Implementation issue per location above
3. Implementation issue to clean up Bootstrap code.