[SQUASHED] Lockscreen Notifications (2/2)

Following commits inside (with minor adaptations)
AOSPAL/android_packages_apps_Settings@10ccffd
AOSPAL/android_packages_apps_Settings@17c7bcf
AOSPAL/android_packages_apps_Settings@db67577
AOSPAL/android_packages_apps_Settings@8fc910a
AOSPAL/android_packages_apps_Settings@a73649a
AOSPAL/android_packages_apps_Settings@9b8a305
AOSPAL/android_packages_apps_Settings@cb18eca
AOSPAL/android_packages_apps_Settings@b2ff326

Change-Id: Ib13c39cb67839bec92a660000eae23bdb7fdfa30