Fix page sizing in left nav panel (Browse & Search)

Some sizing issues in the left nav panel have been reported in the JSF UI.

The system is showing a scroll bar down the right side of the left-nav panel (notably in Search). The top of the scrollbar is cutoff (appears tucked under the header panel). Also, the scrollable area is often far larger than needed (a lot of white space is added to the bottom of the left panel which results in the unnecessary scrolling).