node: Add a Node object
node: Add a Node object

This object can be used to give any other object the ability to be
positioned into a scene (as part of a scene graph).

Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@gmail.com>

dlespiau/dax,dlespiau/dax