Refactor imstk libraries
- Refactor rigid body model config
- Move controllers to separate library
- Use forward declarations: Scene, SceneManager, SimulationManager, collision, geometry, dynamical models, animation, controllers, data structures
- Renaming classes and enums: Core->Common, imstkEntity->imstkSceneEntity etc.
- Move imstkSceneEntity from Common to Scene
Edited by Sreekanth Arikatla