Generate Camera from loaded model

Generate Camera from loaded model

Add API to generete (or apply) the camera what 3D model has.

Note that model cannot have ownership of camera
since we have to add camera into SceneView or whatever we want.
So GenerateCamera create new CameraActor everytime.
Or ApplyCamera into already created CameraActor.

TODO : Should we change all Scene3D::Loader used demo who use camera parameter?

Change-Id: Ief1571d1e8b522c1785b8721c279713b20760a99
Signed-off-by: Eunki Hong <eunkiki.hong@samsung.com>