Logic for building layout header in admin area is duplicated in JS

[ewinslow]

This is not maintainable as is. Furthermore, it's not even correct as is. The title menu cannot be generated correctly for ajax-loaded pages. Need to think more about how that would work. Forcing people to rely on the hook + passing all parameters to the menu explicitly seems like our best shot, but it's very different from how Elgg has done things so far (relying on global state). Maybe this is a good motivation to get away from that frowned-upon approach.