Pin content to drawer #1556

As a user I want to be able to pin any content in the repository to the drawer on the left. When I click on the item, I get the usual explore experience (tree/grid).

What about navigating out of the folder?

• Pin content: from context menus in the tree or grid.
• Unpin content: from the drawer using a pin icon displayed for these custom items (see image below)
• pinned items show up ABOVE the Content menu item
• new pinned item is displayed immediately, without page refresh
• this is a permanent, repository level setting (not user level)
• display: content (type?) icon and display name
• too many items: scrolling, with the bottom (system) items sticking where they are (only the upper part scrolls)

Permissions

• visible for anybody who has See permission for the content
• I can pin any content I see. OR only members of a group? Developers, Editors, Public admins?