New app: Wordpress

@jvalleroy-guest mentioned that we should considering adding Wordpress in #259 (closed).

Wordpress is already in Debian, offers a customizable blogging solution, is generally easier to configure and use than Ikiwiki, and offers tons of extra features through its plug-in market (e.g. RSS feeds can be hosted on a wordpress, videos and pictures can be hosted, visitors can submit responses to forms).

I have two main questions about this:

1. As far as I know, the only reason we don't offer Wordpress is that we haven't had the time to integrate it into FreedomBox. Are there any other reasons not to integrate Wordpress?

2. If people agree that Wordpress is worth adding, is it possible to add it by the Buster freeze? If we don't add it before the freeze, then we'll have to wait two years to get it into the stable image.