Fix -navbar events attachment

Closes #3623
- Move hamburger logic to action with terrible name, "toggleSidebarOrGoHome"
- Move ".js-close-sidebar" events to a document.on(event, *selector*, f) to make sure they attach even when the js-close-sidebars aren't on page (ie, hidenav)
- Moved `hideNav` logic to the view, cause that made sense to me.