Update copyright and funding section

Summary

As mantik user, I want have an up-to-date footer section so I can know the true copyright owners and who is supporting the project.

Acceptance Criteria

• Given I have opened the mantik platform docs When when i look at the copyright section Then I see the "© Copyright 2025, Ambrosys GmbH"
• Given I have opened the mantik platform landing page When when i look at the footer Then I see the logos: ambrosys, eu sterne, euro hpc, bmwf logo (@rico.berner pls attach)
• All other outdated occurrences have been removed, see #325 (comment 2305482772)

Testing

No testing

Additional Notes / Information

Technical Information

Suggested Implementation

• change fields copyright and authors in "docs/source/conf.py" and "docs/source/about.md"
• collect and replace logos
• paper -> ??
• replace in authors with contributor names
• All other outdated occurrences have been removed, see #325 (comment 2305482772)

/cc @rico.berner