Add APEX com.android.tethering.apex for tethering module.
It have tethering apk now and would have jar and library
in follow up CL.

Bug:144320626
Test: build
Change-Id: Ie6158639886e90180dd90347e802a5fe062031b2

To be the unbundled application, tethering can not use UserManagerInternal
method anymore. Replace it by listening user restriction change intent.

Also fix some cleanup from
https://android-review.googlesource.com/c/platform/frameworks/base/+/1131002

Bug: 143195885
Test: -build, flash, boot
      -atest TetheringTests
      -manual test. Add a trigger point to call
       UserManager.setUserRestriction(DISALLOW_CONFIG_TETHERING) from
       Settings. Open hotspot -> restrict tethering from new adding trigger
       point -> hotspot is OFF and Tethering settings are not available.

Change-Id: I4ed08d20f8b7476b8ecd5d018b75806dd2f22cc1
Merged-In: I4ed08d20f8b7476b8ecd5d018b75806dd2f22cc1

Now tethering would be run in dedicated service.
TetheringManager is the interface used to communicate with
TetheringService. The new call flow would be: ConnectivityManager
-> ConnectivityService -> TetheringManager -> TetheringService.
Note: the return value of #tether(), #untether() and #setUsbTethering()
APIs would always be no error. Client can use #getLastTetherError()
or #getTetheredIfaces or listen tether state change to check
status of corresponding interface.

Bug: 136040414
Bug: 144742179
Test: -build, flash, boot
      -atest TetheringTests
      -atest FrameworksNetTests

Change-Id: I7e78c0e0a3e70f940a749ba2a39ece7c7ec5b9b3
Merged-In: I7e78c0e0a3e70f940a749ba2a39ece7c7ec5b9b3

- Statically include android.hardware.tetheroffload.config@1.0,
  libcutils and their dependency library.
- Use shared-lib if there is NDK or NDK-compliant version
- Remove android.hardware.tetheroffload.control-V1.0-java from
  service.core because it is already statically built in tethering apk

Bug: 143195885
Test: -build, flash, boot
Change-Id: Ic082045bc04d3989f7f095c7a499bc0d943e4031
Merged-In: Ic082045bc04d3989f7f095c7a499bc0d943e4031

Both were already statically linked both in the NetworkStack module and
the framework, so this change only reorganizes the file locations.

It makes more sense to have the library files in the NetworkStack module
folder, as changes to these files will be released with the same cadence
as the module, not the framework.

Bug: 139106271
Test: built, flashed, WiFi working
Change-Id: Ifaa882b53d1084ef32db6b27d35b56eb226c468f

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