DDF-939 - Added optional banners to admin ui

-header and footer are optional in the ui.
-This is a more css based approach since we have relative containers on the page.  I added a div wrapper around all non-banner content to help aid in positioning the main content in between the banners if they are enabled.
-added banner less file to handle everything banner related.
-added properties file to mimic implementation in the search ui.  Also will be handy later for admin-wide properties (which we should start using).