Use a proper templating engine/library

[Tar-Minyatur]

At the moment the placeholders in the template are {{{ mustache }}} style, but I created a very simple and stupid helper function to take care of replacing them with the actual values.

I started out using chevron.render() to do this, but unfortunately Mustache considers dots (.) in keys to be an indicator for a nested scope. As we have full paragraphs in our keys, this doesn't work. Another issue was that chevron does not support defining a fallback if a key is missing and just replaces it with an empty string, which I believe we do not want.