Katello pages do not highlight upper level navigation tabs
There is an inconsistency whereby Katello pages do not highlight the upper level navigation tabs but Foreman pages do.
Fixes #6057: highlight active tab based on current URL.
Highlight the active menu tab based on the current URL
rather than relying on the controller and action. This
fixes a problem where top level menus that contain plugin
menu items were not being highlighted when active.