Refactor the way we display the usage_scenario

[ribalba]

Currently take the json object and convert it to yml in the frontend. While this is structurally what the scenario represents it isn't always easy to read and understand. Also we need to unescape things like < as we use them in emails and as we render the code in a pre we can see the unescaped version.

I propose to rethink the whole display and split up the usage scenario into the sections and add some explanatory text. For example we could have the services heading and then link to the documentation and have a little sentence describing what this section does. We should still offer to download the whole file but have this as a little button.

[ArneTR]

Thanks for setting up the issue. I think this is a good first issue for contributors as it mainly involves frontend work. The links we would provide from our side.

For everyone reading this: Happy to provide guidance for any PRs <3