lineage: Deprecate AddonSU

* We are no longer providing our own root access solution
  as of 17.0, as PermissionHub has largely replaced the
  functionallity of Privacy Guard, which this feature
  was housed in.

* We do still have a baked in ADB root solution that can
  be enabled in developer settings (see topic:ten-adbroot
  on Gerrit).

* This DOES NOT mean we will be providing support for other
  root solutions.

Change-Id: Iecf92e3c8f91304ed998e0260d09a8048dc44d82