[Thread] initial Thread network service

This commit sets up the initial Thread network service for the
Android Thread feature which allows an Android device to create
a Thread network and being a Border Router.

See https://www.threadgroup.org/What-is-Thread for background of
Thread.

See b/235016403 for the Android Thread feature request.

Test: lunch aosp_cf_x86_64_tv-userdebug
      m && launch_cvd
      atest CtsThreadNetworkTestCases
Bug: 262683651
Change-Id: Ie1bb23084531f67165ec068ea3ca39592dbc01d1