Update file CITATION.cff

Adding a CITATION.cff file for future users to reference the repository. Please check the file for accuracy, as I was not part of the developement process I may not have had the correct information.

CITATION.cff

+# This CITATION.cff file was generated with cffinit.
+# Visit https://bit.ly/cffinit to generate yours today!
+
+cff-version: 1.2.0
+title: DAA-Notebooks
+message: >-
+  If you use this software, please cite it using the
+  metadata from this file.
+type: software
+authors:
+  - given-names: Robert
+    family-names: Jäschke
+    orcid: 'https://orcid.org/0000-0003-3271-9653'
+    email: robert.jaeschke@hu-berlin.de
+    affiliation: Humboldt-Universität zu Berlin
+  - given-names: Frederik
+    family-names: Arnold
+    email: frederik.arnold@hu-berlin.de
+    affiliation: Humboldt-Universität zu Berlin
+    orcid: 'https://orcid.org/0000-0002-0417-4054'
+  - given-names: Simon
+    family-names: Hachmeier
+    email: simon.hachmeier@hu-berlin.de
+    affiliation: Humboldt-Universität zu Berlin
+  - given-names: Michel
+    family-names: Schwab
+  - given-names: Sebastian
+    family-names: Tiesler
+    email: sebastian.tiesler@hu-berlin.de
+    affiliation: Humboldt-Universität zu Berlin
+repository-code: 'https://scm.cms.hu-berlin.de/ibi/daa-notebooks'
+abstract: Notebooks für MP2 Datenanalyse und -auswertung (DAA)
+license: Apache-2.0
+commit: 15299533794803c9e6f1d6b6f812e738e3a5c4d6
+date-released: '2024-07-09'