Define Feature action for obtaining info on a new CEC device

Feature action (or action) is a unit of CEC command flow that accomplish
a certain feature. This CL introduces an abstract class FeatureAction,
and a concrete one NewDeviceAction that is used to obtain detailed
information on a new logical device on the CEC bus.

Change-Id: I94a7e75fbb76fe547f07f9588a93c7ea5a85d856