Cite us: include current FReD citation

On the following page, the FReD citation should be regularly updated 
https://forrt.org/about/cite_us/

based on this source:
https://raw.githubusercontent.com/forrtproject/FReD-data/refs/heads/main/output/citation.txt

Maybe we can add that to the data processing action and only run this part once a week or on manual runs