lp1422802: Improve visibility of parts on Place Holds screen

lp1422802: 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 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>
Signed-off-by: Ben Shum <ben@evergreener.net>