[blog.mondediplo.net] Add multiple feeds

[ovalenti]

I would like to add a french newspaper blog to the default configs.

The channel was tested as a feeds.yml file, but I could not find a procedure to use it as part of html2rss-web, despite binding /lib/html2rss/configs in /app/config in the container. There must be caching dark magic that I have to learn 😅

Untested in this form.

[gildesmarais]

Thank you! Looks good.

I've added a testing file and merged your changes via #251

Going forward, the process of adding such configurations should be significantly streamlined -- eliminating the need for what currently appears to be opaque or overly complex logic. :)