Re-Add hidden-apps setting

Forward port from CM 10.2
PS3: Don't rename and incorporate changes from Devkota
PS4: Update German translation
PS5: Remove translations
PS7: Hide widgets from widget list
PS9: Remove debug output
PS10: Rebase strings

Change-Id: Ie06b288e22c2678fb09da1bf42d46922b8319e01

Conflicts:
	res/values/preferences_defaults.xml
	src/com/android/launcher3/settings/SettingsProvider.java