Adwaita: colorchooser style rewrite

To reflect latest Benjamin changes. As a bonus the colorchooser
looks better to me, same for the scss code.
Distribute gtk/resources/ui/*.ui.h

POTFILES references them.
Adwaita: color button changes

Dimmed inner colorswatch shadow to make brighter colors looks nice,
increased the padding to make button states more evident, 0 border
radius to match the padding change and no colorswatch shadows when
the button is insensitive.