Take a wrench to the pipes

 - Track extensions in garbage tracking because they could be big
 - Fix volume dialog cleanup to not leak
 - Fix QSFragment cleanup to not leak
 - Make DockedStackExistsListener static because it is going to leak
   because /Binder/
 - Add a secure setting to force on notifications for garbage monitoring
   for those that really really want it.

Test: adb shell dumpsys activity service SystemUI | grep -A 12 LEAK
Change-Id: Id5689febd65eb8a22dbb4a0a15ec051fcdbbf8be
Fixes: 38461559