Ability to display static content

### Description

Great little app!

Would be great if I could insert a "static content" (or even better a `markdown`) widget.

Use case if you're interested is to create a de-facto documentation site. I don't need something massive for managing my little home-lab and having status + releases all on the same page would be ideal (which glance) already provides :)

No file, test, or entry point is named in the issue. Start by locating the existing widget entry points and configuration flow; done means a user can configure static text or Markdown and see it rendered in the dashboard.

Written by the indexing model from the issue text.