Add unique ID to all scene objects through Entity class

Add unique ID to all scene objects. This is necessary for networking. We can create an Entity class that will allow this to be possible.

added Type: new feature label

@sreekanth-arikatla There's a problem here. Currently, lights aren't actually SceneObjects, so it's impossible to synchronize them. Would it be possible to make a base class such as imstkObject that all objects can inherit from? This class can just store a unique ID number for each object. A static variable can be used to keep track of ID numbers.

@NickMilef that I think makes sense. When do you need it by?

I need it pretty soon. I can do an MR today if that helps, it should be an easy fix.

Yes, please do so

mentioned in merge request !297 (merged)

changed title from Add unique ID to all scene objects to Add unique ID to all scene objects through Entity class

changed the description

closed via merge request !297 (merged)

mentioned in commit fa7d2f16