Add TetherConfigParcel to improve tetherStartWithConfiguration

tetherStartWithConfiguration doesn't take a configuration, it
takes a boolean. But for extensibility purposes, it should
take some sort of configuration parcel. This is because in
AIDL, once we add a method we cannot ever change its signature
or add parameters, because there cannot be two methods with the
same name. Create a new parcel to improve this.

Bug: 145777247
Test: atest FrameworksNetTests
Test: atest netd_integration_test:BinderTest#TetherStartStopStatus
Test: build, flash, on/off tethering
Change-Id: I0d34a25fc9a187e218d37a058b8316ea2423a5da
6 files changed