Add support and styling for short “microblog” posts

[AngeloStavrow]

Right now, the theme will sort-of support “microblog” style short updates that have no title, but they don’t look especially nice in the timeline.

The other bit here is how to limit such posts to a rendered 280 characters, so that they play nice with other services to which you might want to cross-post (e.g. Twitter, micro.blog, Mastodon).

Should Hugo throw an exception on building the site if it comes across a post with no title and with rendered content over 280 characters?