Make download of legacy versions less obvious and some other changes

[ann0see]

The legacy builds and old versions of Jamulus should not be preferred, so this makes them less prominent

Short description of changes Smaller and bigger changes. Makes the download of the legacy build less obvious (we might even want to remove the link in the .yaml file). I assume that we will need to remove the legacy build soon.

Context: Fixes an issue? Related issues No

Status of this Pull Request Ready for review

What is missing until this pull request can be merged?

Visual test, review Does this need translation? YES

Checklist

• [x] I've verified that this Pull Request follows the general code principles
• [ ] I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• [ ] I'm sure that this Pull Request goes to the correct branch

[ann0see]

Thanks. Fixed and merged