Added banner to list if front matter is present

[lamATnginx]

Proposed changes

Closes https://github.com/nginxinc/docs-platform/issues/489

Checklist

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• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)

[github-actions]

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[danielledeleo]

I like how the frontmatter works, that's a nice solution. I'd like to see if we can do this without adding another shortcode that is just another way to invoke callouts.

[nginx-jack]

I like how the frontmatter works, that's a nice solution. I'd like to see if we can do this without adding another shortcode that is just another way to invoke callouts.

Yeah, since it's almost identical to a call out at the moment, I'd call the calllout.html partial from the banner.html partial. Maybe have the banner partial only handle the banner specific things, like the date, reading the markdown file, and then pass it directly to callout.html, since it already calls markdownify, so that case should be handled.