Add (3.0) [models] examples

[Andre-LA]

• [ ] models_animation
• [ ] models_billboard
• [ ] models_box_collisions
• [ ] models_cubicmap
• [ ] models_first_person_maze
• [ ] models_geometric_shapes
• [ ] models_material_pbr
• [ ] models_mesh_generation
• [ ] models_mesh_picking
• [ ] models_loading
• [ ] models_orthographic_projection
• [ ] models_rlgl_solar_system
• [ ] models_skybox
• [ ] models_yaw_pitch_roll
• [ ] models_heightmap
• [ ] models_waving_cubes