Remove or upgrade Bootstrap JavaScript bundle

We load the Bootstrap JavaScript bundle for a few things:

• Tooltips in tier badges and the "copy to clipboard" script.
• Expand/collapse on "Version history" sections
• Expand/collapse on menu items
• Expand/collapse on "Help & Feedback" box
• Scrollspy on the ToC (https://getbootstrap.com/docs/4.0/components/scrollspy/)
• Close button on the alert banner

Could we retire Bootstrap in favor of GitLab UI components? Or should we just upgrade to 5.x? Moving to 5.x would at least allow us to drop our jQuery dependency.

In 5.x, we could import Bootstrap components more selectively, like this: https://getbootstrap.com/docs/5.3/getting-started/vite/#import-bootstrap