This package is using some common utilities from
a library that used to live in the network stack.
A better home for these utilities is frameworks/libs,
so this topic moves the files ther and also changes
the package of some utilities.
See aosp/1350222 and aosp/1350182 for a detailed
description of the specific files that moved.
Test: checkbuild
Change-Id: I76a9b7790f3997e3e6b3c2f75ba6308286457cde
Add a simple test to verify that IDs loop correctly, that they skip used
IDs correctly, and throw when there is no remaining ID.
Test: atest com.android.server.NetIdManagerTest
Change-Id: I4c9518c725156d743286e062fd2eec1423a0459e
