[1/2] Block apps from changing lockscreen pass

1. android_frameworks_base
2. android_packages_apps_settings

Added option in Settings > Security > Device Administation > Block Apps from Changing Locscreen Password to disable or change password remotely by Device Administrator Apps. This o
ption is disabled by default. Apps will be informed that password change failed.

Conflicts:
	core/java/android/app/admin/DevicePolicyManager.java