[Tether09] Use INetd to call netd directly

- Using INetd to communicate with netd directly instead of using
NetworkManagementService which is a wrapper of INetd and don't have plan
to be updatable.
- Also replace InterfaceConfiguration by InterfaceController.
- Remove redundant interface flags. Only set interface up/down flag to
netd because netd only use these two flags for INetd#interfaceSetCfg.
- Note that tethering still use NetworkManagementService
to register tethering stats provider and it would also be replaced with
other way in follow up change.

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

Change-Id: I4ab0ad387d4bd1773ff94d3b380c1720df07f8d5
Merged-In: I4ab0ad387d4bd1773ff94d3b380c1720df07f8d5