Adjust permissions on Metadata metrics

[NicoledeGreef]

As discussed, let's remove access to "Metadata metrics" report from any roles that are not Catalogue admin or Catalogue information management specialist.

Originally posted by @NicoledeGreef in #525

• Modify the app so that only users with either the Catalogue admin* or Catalogue information management specialist roles can see/access the "Metadata metrics" tab from their Dashboard
• Adjust documentation so that it is clear that only users with the Admin or Info management specialist roles have access to the "Metadata metrics" tab.