Add a newsbox

[toby63]

Just an idea related to #134.

What do you think of adding a newsbox to the home page? It is like a sidebar showing the latest news, here is an example: https://www.cmsimple.org/doku/en/?Working_with_CMSimple___Newsboxes

It could show only the most important news, such as releases and security notes etc.

We could maybe implement this, with:

• categories for the blog (so we can differentiate between news and blog posts (e.g. development blog entries (if they ever exist))
• iframe or some other solution for the newsbox, if there is no native solution in hugo

[Krzmbrzl]

Featuring the most recent blog post on the main page is probably a nice addition