Hide notification icons from statusbar

When long pressing a notification, add another menu item which allows the user to hide
the notification icon while keeping the actual notification in the dropdown

This is meant for applications which have services running
in the statusbar which the user is aware of, so right now
we hide the icon by the package

Credit/Thanks to @romanbb

Change-Id: I41f81255fd835ce1ba661e481529b1def8b0b938

Conflicts:
	packages/SystemUI/res/menu/notification_popup_menu.xml
	packages/SystemUI/res/values/custom_strings.xml
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java