[Tizen][Scene3D] Make ModelNode and Light as Control

[Tizen][Scene3D] Make ModelNode and Light as Control

Since we need to use some control features (like KeyboardFocus) let we make
ModelNode and Light as Control, instead of CustomActor.

TODO : We'd better make some universion Control for Scene3D.
For example, we should not allow to add Visual into ModelNode or Light.

Change-Id: I8acbb57d967c438101fe8a1877950d044ca943f2
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>