ODRL for Five Safes RO-Crate

Placeholder issue as we've discussed this a few times but don't seem to have a dedicated issue yet - somewhat related to #194.

Could build upon work by ODISSEI who have defined a "Five Safes license" using ODRL:
* GitHub machine-readable version: https://github.com/odissei-data/ODISSEI-Five-Safes-license?tab=readme-ov-file 
* Human readable version: https://doi.org/10.5281/zenodo.18456775