Add list of PaN facilities data policies

Initial list from 10.5281/zenodo.4014811 + recent additions (e.g. DESY):

RI	Data Policy
DESY	10.3204/PUBDB-2025-02183
PSI	PSI Data Policy
Diamond	obsolete link
ISIS Neutron and Muon SOurce	Data Policy
SOLEIL	Data Management Policy
ALBA	Data Policy
HZB	Data Policy
HZDR	Data Policy
MAX IV	Experimental Data Policy
Elettra	Scientific Data Policy
ESRF	10.15151/ESRF-DC-1534175008

Edit: ⚠️ This issue is now closed, the up-to-date links to the facilities data policies are kept in the data repositories table of leaps-wg3 webpage, first column. Please open a new issue if you need to update your link.