Brings back site information to the header (site name / MODX version)

Based off ideas from #11850
I'd rather use `Ext.get('modx-manager-search');` (which returns an `Ext.Element`) for code readability.
You then would be able to use [`uberbar.isVisible()`](http://docs.sencha.com/extjs/3.4.0/#!/api/Ext.Element-method-isVisible) to check the element visibility.