Add 'New Section' button to article placement UI

Hey Team,

Loving the new article placement UI that comes with this EAP.  It would be 100x even more useful if you could add in a “New Section” button that allows us to create a new section on the fly without having to backtrack out of the article placement window to create the new section and then come back in. 

This would make this a lot more intuitive and save time for guide managers. I often find 50% of the new time I'm creating a new section when building out a new HC with content.