Register broadcast receivers for PACKAGE_ADDED/UID_REMOVED on all users.

The package and uid removed broadcast receivers are only registered in
the primary user. Packages added and removed on secondary users are
ignored. This is unsafe given that new packages can be granted the uid
and the old policy applied to it. This addresses the problem by
registering broadcast receivers for PACKAGE_ADDED and UID_REMOVED for
all users.

Test:
1. Create a new user
2. Install a new app in the user
3. Apply background data restriction uid policy
4. adb shell cmd netpolicy list restrict-background-blacklist
5. Uninstall app
6. adb shell cmd netpolicy list restrict-background-blacklist

Change-Id: I8c87fcf0310fe1fc07095fdc599af10ba0a3d959