Add Kadi4Mat in spotlights

Kadi4Mat is an open-source software for managing research data.

• Review link

Checklist for authors

• Add a link pointing to the review app

Checklist for reviewers

• Reference the corresponding issue in MR
• File size of images is not too large
• Update date_added attribute
• Centres are referenced by official names
• License is named by SPDX identifier if possible
• All links are pointing to the right place
• Code blocks and headlines surrounded by newlines

/cc @frust45 @konrad @jandt-desy @christian.meessen

_layouts/spotlight-list.html

@@ -73,7 +73,7 @@
                 </p>
                 <p>
                     Please note that this list will not be extended any further.
-                    Currently, we are preparing the <a href="https://helmholtz.software" target="_blank">Helmholtz Research Software Directory</a> to accommodate the Software Spotlights in the near future (Q1/2023), aiming to provide more features and a better user experience.
+                    In early 2023, we set up the <a href="https://helmholtz.software" target="_blank">Helmholtz Research Software Directory</a> to accommodate the Software Spotlights in the near future, aiming to provide more features and a better user experience.
                 </p>
             </article>