[Tether08] build InProcessTethering package

Build tethering package which is running the same process as system
server.
Since tethering still have some dependency with system server which
need to run in system server process(e.g. use LocalService), we
need to use InProcessTethering for all first. After cutting off
the dependency, Go devices would keep use "InProcessTethering" and
other non-Go devices would be switched to use "Tethering" package.

Bug: 136040414
Test: -build, flash, boot
Change-Id: I680273a3ee8fed3af843a829da17ca84b130f475