Improve visibility of parts on Place Holds screen

Improve visibility of parts on Place Holds screen

Users often miss the list of parts on the Place Holds screen, leading to
many title-level holds on records where only one or two libraries have
'unparted' copies. This branch adds some styling to add padding around the
parts selector and to bold the Select a Part text. Many thanks to Christine
Morgan whose custom work at NOBLE served as an inspiration for this styling.

The branch also adds a new config.tt2 option to display select parts with
radio buttons instead of a select menu so that all of the parts will display on
the screen. With this option, no parts are pre-selected, forcing the users to
actively choose a part.

Signed-off-by: Kathy Lussier <klussier@masslnc.org>