[e.cash] Add featured styling to blog post list

Summary:
Adding some color highlighting to featured blog posts in the list view on /blog
The attribute is controlled in strapi and if its there, the post will be highlighted in purple and have a star next to it

Also adjusting the top card layout to feature the featured posts. Now it shows latest 3 posts, then any featured posts

Test Plan: preview and check /blog. A handful of posts have the new attribute and should appear purple, and the featured posts should appear at the top

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D19543