refactor: scripts

[mfranzke]

Proposed changes

We should further differentiate the scripts we're providing:

• Test screenshots should be possible to get generated more specifically, either easily and simply or by doing a rebuild after facing problems.
• clean should do a git clean again, as the current simplified one does lead to problems on a quite frequent basis.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (fix on existing components or architectural decisions)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Further comments

[github-actions]

🔭🐙🐈 Test this branch here: https://db-ui.github.io/mono/review/refactor-scripts

[mfranzke]

@annsch, as it looks good to you, would you please also leave your approval here?