Add a linked image content type

[tynandebold]

Description

Resolves #145

Development notes

I've added new content type called LinkedImage. That's fetched from GraphQL and then rendered on the page.

Question for @stichbury: do you want to be able to specific if the link opens in a new tab or not?

QA notes

Take a look at the test article here to see it in action: https://deploy-preview-147--kedro-website.netlify.app/blog/test-article-dont-publish

Checklist

• [ ] Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• [ ] Added tests to cover my changes, where applicable

[netlify[bot]]

✅ Deploy Preview for kedro-website ready!

Name	Link
🔨 Latest commit	16ff773092bbc15d76d1b29b7cff148cd4d94a4a
🔍 Latest deploy log	https://app.netlify.com/sites/kedro-website/deploys/649ea83fc452c80008bb786b
😎 Deploy Preview	https://deploy-preview-147--kedro-website.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.