Insert/remove packages from new/deleted users to/from restricted networking mode's allowlist

In restricted networking mode, when a user is created, its packages are restricted by default.
This change allows packages with the INTERNET permission.
On the other hand, when a user is deleted, the UIDs are removed.

Test:
1. Create new user
2. adb shell settings get global uids_allowed_on_restricted_networks
3. Delete user
4. adb shell settings get global uids_allowed_on_restricted_networks
Change-Id: I5999e5ada12955a46b7e6797261c5ee3788c623d

Change-Id: Ic096621f1f08863f62159ea651eed5b0ecf633cb