feat(design): automatically add anchor link and copy URL button to article headings

[joannalauu]

PR Checklist

• [x] Commit message follows our contributing guidelines
• [x] Tests added/updated (for bug fixes/features)
• [ ] Documentation added/updated (for bug fixes/features)

PR Type

• [ ] Bug fix
• [x] Feature
• [ ] Style update
• [ ] Refactor
• [ ] Test
• [ ] Build
• [ ] CI
• [ ] Docs
• [ ] Performance
• [ ] Other (please describe)

Current behavior

Fixes: #3973

New behavior

• Added anchor link to article heading that directs user to that heading on click.
• Added button next to article heading that copies the heading URL to clipboard on click
• Anchor links and buttons are automatically added to all <h2>, <h3>, <h4> headings in DaffArticleComponent by default, but can be removed by adding a nolink attribute into the element

Breaking change?

• [ ] Yes
• [x] No

Additional context