Bug: 144455789
Test: Build pass.
      atest TetheringConfigurationTest (PASS)

Change-Id: I9ab4c7b3aef0619046d7e3d711683dbe1f31bb50

1. getTetherApnRequired API rename to isTetherApnRequired.
2. Expose isTetherApnRequired API as system API.

Bug: 142365448
Test: Build pass.
      atest TetheringConfigurationTest (PASS)

Change-Id: Iafb2e4fbddb0251e23673742d990ad098a8ae375
Merged-In: Iafb2e4fbddb0251e23673742d990ad098a8ae375

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

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

Change-Id: Ic1d9deecb66aaba0a4264a57f2e6579ea491ac9b

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

Change-Id: Ifdfc6cd95377351c37946a146b60896f07ece59d
Merged-In: Ifdfc6cd95377351c37946a146b60896f07ece59d

Add IpServer which is used to serve ip configuration, dhcp, dns proxy
and nat for downstream interface.

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

Change-Id: I23652ae0b9509abe7d38da96d523eb22ab00a343

TetheringConfiguration is a utility class to encapsulate the various
configuration elements.

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

Change-Id: I9434ab213bc5e0fca59f14a6c8cea554abefc3a4

This is initial patch that don't contain any service for now.

Bug: 136040414
Test: -build, flash, boot
Change-Id: I0b49d7e9c3fcba5af3025163f9cc9eafb0778116