RSS Feed adjustments and "connect to portal" change

We have adjusted feeds, they now include DOI and issue number.

There have also been two changes in the connect to portal function:

Expositions which are private can no longer be connected to a portal, the exposition has to be shared in some manner (within the portal, RC or with the public). This to avoid the situation where a user tries to connect (by accident) a private exposition, which would not even be visible to the admin nor to anybody else. The share status is now visible to portal admins under “connection requests”, for better overview of who can see the exposition.