Asset swap and make SearchView use themed context

- Make SearchView in action bar in People app use action bar
themed context so the query text and icons are white instead
of gray. Create a custom theme to make the hint text lighter
than the default DarkActionBar hint text color (as directed
by UX and framework)

- Replace panel_message asset (background of contact editor on
tablet and contact unavailable fragment)

- Replace the panel_content asset (background of group detail
fragment)

Bug: 5127109
Bug: 5199518
Change-Id: Icae927e1d158241140d18028d38cac25dbf282fc