Split mobile and wireless bridges
Split mobile and wireless bridges

Split the mobile and wireless bridge create and destroy paths into two
separate ones, harnessing the refactored helper functions. This enables
the wireless tap devices to cohabit the same bridge on the same subnet,
and leaves the 1:1 tap/bridge setup intact for mobile interfaces

Mobile interfaces are changed to set the gateway IP on the tap
interfaces instead of the bridge interfaces, which are also removed. At
the same time, remove the spawning of DHCP servers on mobile interfaces,
which were never used.

Note that this change requires a new launch_cvd which reads the mobile
network setup from the tap device before falling back to the bridge
device for backwards compatibility.

Signed-off-by: Alistair Delva <23ee790dfac9f550e53930edf0f667e54338af85@google.com>

google/android-cuttlefish,google/android-cuttlefish,google/android-cuttlefish,google/android-cuttlefish,google/android-cuttlefish,google/android-cuttlefish,google/android-cuttlefish