Change Tethering package name

".apex" is easy to confuse.
Rename as below:
apex: com.android.tethering.apex -> com.android.tethering
apk: com.android.tethering -> com.android.networkstack.tethering

Bug: 146471733
Test: build

Change-Id: I2c7647abb996539a3af6cfe0e0214a5e8927c0d6
17 files changed