fb: common slim classes

all system shortcut icons we need for this and other stuff in future
basice slim helper and constants classes we need later as well
device utils helper
preparation for navbar navring and other shortcut features

xxhdpi icons thanks to kroz again

Change-Id: Ie552480007bde649352c699c8ff9ac10e79ed069

Conflicts:
	core/java/com/android/internal/util/slim/ButtonsConstants.java
	core/java/com/android/internal/util/slim/ButtonsHelper.java
	core/java/com/android/internal/util/slim/DeviceUtils.java
	packages/SystemUI/res/layout/status_bar_expanded.xml
	packages/SystemUI/res/values/colors.xml
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/ShortcutsWidget.java