Fix/update download

Description

Applies a new structure to download section, updates requirements and allowed branch names for MRs

Testing Instructions

1. [Step 1: use mkdocs serve to see website]
2. [Step 2: have a look at the download sections an merge requests]

Developer Checklist

• Code has been tested locally and/or in pipeline.
• Merge conflicts resolved with the target branch.

requested review from @kristina.mazur and @AndiGob

assigned to @kbistreck

approved this merge request

Looking good

merged

mentioned in commit 3dc576bf