Move EE differences for `app/views/projects/commits/show.html.haml`

What does this MR do?

CE counterpart of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/12960/

Move EE differences for app/views/projects/commits/show.html.haml

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/10444