Add output mark to XfrmController

Adds the ability for XfrmController to set output marks, to allow
support for VTIs. This change uses the underlying networkId field
(renamed from underlyingNetwork), for which the System Server currently
passes the netid of the underlying Network.

Bug: 72392543
Test: All tests (CTS + unit tests) passing
Change-Id: I76fe052ecf0fc193f07713a2ea31a4ad58fc9ff9
6 files changed