First pass at using VS Code UI toolkit

[charisk]

Start using the VS Code Webview UI toolkit instead of Primer.

This change covers:

• Using VSCodeBadge instead of our custom Badge component
• Using VSCodeButton instead of our custom ActionButton
• Using VSCodeLink instead of Primer's Link

More changes around migration of other components will happen in future PRs.

Checklist

N/A:

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[shati-patel]

Thanks! Looks good overall—just a question/comment about the styling of links 🖼️ 📝

[aeisenberg]

Tried it out and everything looks good. I like how so few things need to change for this.