configuration option for common landing collection location

[trel]

For deployments where Metalnx is used to commonly access shared information... it would be nice to have a landing page after login that looks the same for everyone - a 'Home' that is not their 'home collection'.

This would affect:

• where users land after login
• where the home icon links to in the breadcrumbs
• where the 'Collections' left side bar links to

Perhaps called in metalnx.properties... metalnx.default_landing_collection

[michael-conway]

This is virtual collections!

The notion would be that the new collection browser could respect virtual collections, and part of this is that virtual collections can have a 'header' set that is determined via grid admin as a common set. So my grid could say that every user sees collections A, B, C plus collections associated with their iRODS groups plus stuff shared with them plus their own stuff.

We had inklings of this in cloud browser and part of this I would argue is formalizing simple, clean conventions for virtual collections. Bonus it would rock.

[korydraughn]

Similar to https://github.com/UtrechtUniversity/davrods/blob/eb48cb684690d9d28daa4f5278694d9291ac993a/aux/deb/davrods-vhost.conf#L126-L139