Add microblogging ability

[MinchinWeb]

Add the ability to "microblog".

Microblogging is generally considered to be blog posts, but very short in length.

The most common example is Twitter, with an original limit of 140 characters (to be less than the SMS max of 160 characters). Twitter has since doubled their limit to 280 characters. The default on Mastedon is 500 characters, the same as (newly released) Threads.

(Note that on Twitter, all links are run through a shortener and so are 23 characters long.)

Micro blog posts don't typically have titles, so the theme layout, slug generation, and RSS feed generation may all have to be alerted to deal with that. (On Pelican, all slugs must be unique.)