R1:de4e8728b2fa

Add ActionIcon to PHUIListItemView, use in Dashboards

Summary: Extends PHUIListItemView to take an icon, link as an "Action Item" that displays on the right side of the menu link. Does not display on Favorites. This allows for adding edit, external, or other links (documentation?) to any menu item. Right now the secondary link is only visible when the item is selected. This feels right, but if we offer it in other ways, users may always want it visible. We could look at making it onhover.

Test Plan:
Add…