TestBed: Add more than one file when generating Q&A

[gotsysdba]

Checklist

• I have searched the existing issues for similar feature requests.
• I added a descriptive title and summary to this issue.

Summary

This may not be possible, but look into ability to add more than one file during Q&A generation.

Why?

Reduce time to generate Q&A

How?

Streamlit, allow multiple file select (easy)
Giskard, process more than one file at a time (maybe hard)

Additional Context

No response