Blog sharing features: RSS feed, Twitter cards, newsletter sign-up prompt

[BeckyPollard]

! Closed, combining PRs  !

Draft Status: 🟢 Add RSS feed to social links. 🟠 Set up Twitter card support. ⚪️ Newsletter opt-in prompt.

Status legend

🟢 Task done
🟡 Task almost done, soon!
🟠 Task started
🔴 Blocked / Seeking advice
⚪️ Not started yet

---

RE: Add RSS support, Apply meta-data to blog pages head for socials, Add newsletter opt-in

Summary of changes:

• Add an RSS feed link to socials that serves evently.cloud/feed.xml atom feed
• Add Twitter card support for blog posts

---

Feedback, nitpicks, and/or corrections encouraged. 🤖

[netlify[bot]]

✅ Deploy Preview for evently-preview ready!

Name	Link
🔨 Latest commit	ad7f5dc4a83ddd666a5e43b454a57b3d57f90664
🔍 Latest deploy log	https://app.netlify.com/sites/evently-preview/deploys/636ed463a4b014000aaa4153
😎 Deploy Preview	https://deploy-preview-47--evently-preview.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 settings.