Settings: Root appops access in developer settings

 * Allow users to directly access the root app settings,
    as the feature is mostly unknown and often a reason
    for users to try using alternatives to CM root

 * Use the appops extra intent to link the su tab,
    introduced in I79d963ecbadc624dc45a398387a348691318b6be

Change-Id: Ia5bc9d56fb11700b19d73336fad13c0a936091ff
Signed-off-by: Adrian DC <radian.dc@gmail.com>