Update Metadata

[mehmetcanay]

Update metadata with the following changes:

• The table currently reflects values extracted from the reference of the paper on cohort studies. Update these entries with the actual values from the participant-level data.
• The FollowUpIntervals column uses days, years, and months. Update the entries so that they will use days (if less than 30 days) and months.
• Remove UK Biobank because it is not necessarily a PD cohort.
• DATATOP's access link is incorrect and re-directs to our mapping sheet. Please update the access link.
• OPDC's DOI link is missing 'h' at the start.
• Change PRoBaND's link to https://www.dpag.ox.ac.uk/opdc/team/proband-tracking-parkinsons
  
• Add Idiopathic PD column.

[mehmetcanay]

@marjanniazpoor for now tackle the first two items, then we can check if there is still a need to implement the third item.

[mehmetcanay]

@marjanniazpoor please also remove UK Biobank as this is not a PD cohort.