[Tether06] Migrate tether offload controller into module

The tether offload JNI library in this patch still have many dependencies
with internal libraries. Will have follow up changes to cut the
dependencies to let it be a unbundled library.

Bug: 136040414
Test: -build, flash, boot
      -atest TetheringTests
      -atest FrameworksNetTests

Change-Id: Iacf8e0b94135e35672de3ee77c474ee39a00c591