Add a Blog List tab that shows all subscribed blogs
When a blog from Available Blogs (#413 (closed)) has been clicked, it will be added to the "Blog List" tab. Here all subscribed blogs should be shown.
(1) unread messages with latest posts first (2) date of last post
Implement possibility to pin an element to the top
(1) pinned blogs (2) unread messages with latest posts first (3) date of last post