Add Resource Pack (Stimulus Package #1 of forum)

Add Resource Pack - Stimulus Package #1 of forum.
- Fix 3D models.
- Added Script editor menu selection for new entities.
- Added Exhibitor model. (source + compiled)
- Added Exhibitor model materials. (+ textures)
- Added Geometries models. (source + compiled)
  - Box x2
  - Capsule x2
  - Cone x2
  - Cylinder x2
  - Plane x1
  - Pyramid x2
  - Sphere x3
  - Teapot x2
  - Tetrahedron x2
  - Torus x2
  - TorusKnot x2
- Added Default texture.
- Added 3 scenes to test light, textures, shaders...
- Added 2 prefabs of lights for global sun.
- Added 10 metal materials.
- Added 1 metal detail material. (+ textures)
- Added 10 color materials.
- Added 30 dev materials. (+ textures)
- Added 3 color test materials. (+ textures)
- Added 4 default materials for test. (+ textures)
- Added 4 default sub materials for test. (+ textures)
- Added 4 detailed materials for test. (+ textures)
- Added 4 detailed sub materials for test. (+ textures)
- Added 8 generated materials for test. (+ textures)